2022年01月, 茨城大学 学長学術表彰

2021年03月, 日本農薬学会 業績賞(技術)

2008年01月, 日本分析化学会 関東支部 新世紀賞

2007年11月, クロマトグラフィー科学会 奨励賞

Development of a new extraction method and functional analysis of phycocyanobilin from unique filamentous cyanobacteria　　　　　　　　　　　　　　　
J. Aoki; T. Yarita; M. Hasegawa; M. Asayama
J. Biotech, 2024年11月, ［査読有り］

親水性－親油性バランス型充填剤を用いた簡便な固相抽出精製による二枚貝中オカダ酸群の精密定量　　　　　　　　　　　　　　　
鳥居塚南; 上原由理香; 長谷川守文; 渡辺卓穂; 鎗田孝, ラスト(シニア)オーサー
分析化学, 2024年04月, ［査読有り］

Assessment of the long-term stability of pesticide residues under freezing conditions in brown rice and soybean certified reference materials
T. Otake; Y. Aoyagi; T. Yarita, ラスト(シニア)オーサー, Pesticide Science Society of Japan
J. Pestic. Sci., 2024年02月, ［査読有り］

Coproduction of lipids and carotenoids by the novel green alga Coelastrella sp. depending on cultivation conditions
M. Saito; H. Watanabe; M. Sasaki; M. Ookubo; T. Yarita; M; Shiraiwa; M. Asayama, Elsevier
Biotech. Rep., 2023年03月, ［査読有り］

Characterization of diarrhetic shellfish toxins in the mizuhopecten yessoensis (scallop) midgut gland by high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS)　　　　　　　　　　　　　　　
T. Yarita; S. Inagaki, 筆頭著者
Anal. Lett., 2023年02月, ［査読有り］

Applicability of superheated water extraction for the quantification of pesticide residues in leafy vegetables
T. Yarita; A. Hasegawa; H. Tada, 筆頭著者, Jpn. Soc. Anal. Chem.
Anal. Sci., 2021年11月, ［査読有り］

Internationally harmonized certified reference materials and proficiency testings for pesticide residue analysis　　　　　　　　　　　　　　　
T. Otake; T. Yarita, ラスト(シニア)オーサー
J. Pestic. Sci., 2021年08月, ［査読有り］, ［招待有り］

Characterization of scallop midgut gland certified reference material for quantification of diarrhetic shellfish toxins
T. Yarita; S. Inagaki; A. Miyamoto; T. Yamazaki; M. Kawaguchi; H. Uchida; A. Takatsu; T. Suzuki, 筆頭著者, A scallop midgut gland certified reference material, NMIJ CRM 7520-a, was developed for validation and quality assurance during the inspection of shellfish for diarrhetic shellfish toxins. The candidate material was prepared by using naturally-toxic and nontoxic boiled midgut glands spiked with okadaic acid (OA). The homogeneity and stability of the material were found to be appropriate. For the characterization of OA and dinophysistoxin-1 (DTX1), nine participants were involved in a co-laboratory study based on the Japanese Official Testing Method, where the compounds were assayed by liquid chromatography-tandem mass spectrometry following alkaline hydrolysis. The analytical values were obtained by the standard addition method with a standard spiking solution calibrated using the standard-solution certified reference materials OA and DTX1. The certified concentrations with expanded uncertainties (coverage factor k = 2, approximate 95% confidence interval) were determined to be (0.205 ± 0.061) mg/kg for OA and (0.45 ± 0.11) mg/kg for DTX1., Elsevier
Food Chem., 2019年11月, ［査読有り］

Proficiency testing by the National Metrology Institute of Japan for quantification of pesticide residues in grain samples from 2012 to 2018
T. Otake; T. Yarita; Y. Aoyagi; N. Hanari; A. Takatsu, From 2012 to 2018, proficiency testings (PTs) were carried out to support the analytical skill development of participants. Grains were sprayed with various target pesticides and used as material samples for PTs. It was found that 27-56% and 10-43% of participants used the Japanese official multiresidue method and a solid-phase extraction technique with the Quick, Easy, Cheap, Effective, Rugged, and Safe (modified QuEChERS, known as "STQ" in Japan) method, respectively. Reported results were evaluated using two types of z-scores: one was based on consensus values calculated from the analytical results reported by the participants, and the other was based on values obtained by the National Metrology Institute of Japan (NMIJ). Acceptable z-scores based on the consensus values and NMIJ reference values were achieved by 78-95% and 67-94% of the participants, respectively. Many laboratories improved their z-scores by continuing participation in our PT. (C) Pesticide Science Society of Japan, 日本農薬学会
J. Pestic. Sci., 2019年08月, ［査読有り］

Comparison of assigned values from participants’ results, spiked concentrations of test samples, and isotope dilution mass spectrometric results in proficiency testing for pesticide residue analysis
T. Yarita; T. Otake; Y. Aoyagi; N. Takasaka; T. Suzuki; T. Watanabe, 筆頭著者, The Hatano Research Institute (HRI) at the Food and Drug Safety Center has recently organized a series of proficiency-testing (PT) programs called the "External Quality Control for Food Hygiene" in order to evaluate the analytical capability of testing laboratories that inspect food samples in accordance with the Food Sanitation Act. In one of these programs, Pesticide I, consensus values calculated from the participants' analytical results were used as assigned values, and the spiked concentrations of the prepared test samples were used for evaluating variation among individual participants. In the present study, the values obtained in the 2013-2015 rounds have been assessed by comparing the analytical results of the target pesticides obtained by using two different isotope-dilution MS (IDMS) methods. These two IDMS methods are based on a combination of different pretreatment protocols and different GC separation columns. The weighted means of the observed analytical results were higher than the corresponding assigned values, but showed good agreement with the spiked concentrations. These results indicate that the spiking concentrations of the test sample from HRI are reliable, and therefore, these values can be used to evaluate the trueness of the participants' analytical method., AOAC Int.
J. AOAC Int., 2018年07月, ［査読有り］

Interlaboratory comparison of liquid chromatography-tandem mass spectrometry quantification of diarrhetic shellfish toxins in scallop midgut glands
T. Yarita; S. Inagaki; T. Yamazaki; M. Kawaguchi; H. Uchida; A. Takatsu; T. Suzuki, 筆頭著者, Elsevier
Food Chem., 2018年06月, ［査読有り］

Difference between consensus value of participants’ results and isotope-dilution mass spectrometric results in proficiency testing for pesticide residues in husked wheat
T. Yarita; T. Otake; Y. Aoyagi; M. Numata; A. Takatsu, 筆頭著者, Proficiency testing was organized by the National Metrology Institute of Japan (NMIJ.) as a measure of analytical competency in the quantification of pesticide residues in husked wheat powder. Seventy-one participants submitted analytical concentrations of the target pesticides (diazinon, fenitrothion, malathion, and etofenprox) along with details of the analytical method employed. Two types of assigned values were obtained for each target pesticide, i.e., the participants' analytical results and the results obtained by NMIJ based on isotope-dilution mass spectrometry (IDMS). The former values were lower than the latter due to the incomplete recovery yield of the target pesticides during the pretreatment process. The discrepancy between the two assigned values was particularly pronounced for malathion because of the longer duration of water-soaking used for the test samples. Two corresponding types of z-scores were then calculated to evaluate the analytical performance of the participants, where the z(1)-score indicates the performance of a participant relative to all participants, and the z(2)-score indicates the relative deviation of the analytical results of the participant from the IDMS value., Jpn. Soc. Anal. Chem.
Anal. Sci., 2016年05月, ［査読有り］

Proficiency testing for quantification of pesticide residues in treated brown rice samples: Comparison of performance of Japanese official multiresidue, modified QuEChERS, and QuEChERS methods
T. Otake; T. Yarita; T. Sakamoto; M. Numata; A. Takatsu, To support analytical skill development, testing of proficiency in pesticide residue analysis in brown rice was conducted for 86 participating Japanese laboratories. Brown rice test samples containing three target pesticides (etofenprox, fenitrothion, and thiamethoxam) were distributed to participants who were free to choose an appropriate analytical method. Reported results were evaluated using a z-score based on the consensus values calculated from the participant analytical results and a z-score based on the high-reliability reference values determined by the National Metrology Institute of Japan (NMIJ). It was found that 80-89 and 82-85% of participants achieved acceptable consensus-value-based and NMIJ-reference-value-based z-scores, respectively. More than 80% of participants reported results obtained using the Japanese official multiresidue method, solid-phase extraction technique with the Quick, Easy, Cheap, Effective, Rugged, and Safe (modified QuEChERS) method or QuEChERS method. We show that the concentrations determined by the NMIJ using these three methods combined with isotope-dilution MS having high reliability agreed well and that the method performances were comparable., AOAC INT
J. AOAC Int., 2016年05月, ［査読有り］

Evaluation of the impact of matrix effect on quantification of pesticides in foods by gas chromatography-mass spectrometry using isotope-labeled internal standards
T. Yarita; Y. Aoyagi; T. Otake, 筆頭著者, The impact of the matrix effect in GC-MS quantification of pesticides in food using the corresponding isotope-labeled internal standards was evaluated. A spike-and-recovery study of nine target pesticides was first conducted using paste samples of corn, green soybean, carrot, and pumpkin. The observed analytical values using isotope-labeled internal standards were more accurate for most target pesticides than that obtained using the external calibration method, but were still biased from the spiked concentrations when a matrix-free calibration solution was used for calibration. The respective calibration curves for each target pesticide were also prepared using matrix-free calibration solutions and matrix-matched calibration solutions with blank soybean extract. The intensity ratio of the peaks of most target pesticides to that of the corresponding isotope-labeled internal standards was influenced by the presence of the matrix in the calibration solution; therefore, the observed slope varied. The ratio was also influenced by the type of injection method (splitless or on-column). These results indicated that matrix-matching of the calibration solution is required for very accurate quantification, even if isotope-labeled internal standards were used for calibration. (C) 2015 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
J. Chromatogr. A, 2015年05月, ［査読有り］

Certification of reference materials for the determination of alkylphenols　　　　　　　　　　　　　　　
N. Hanari; K. Ishikawa; Y. Shimizu; S. Otsuka; R. Iwasawa; N. Fujiki; M. Numata; T. Yarita; K. Kato, Springer
Anal. Bioanal. Chem., 2015年02月, ［査読有り］

Proficiency testing for determination of pesticide residues in soybean: Comparison of assigned values from participants' results and isotope-dilution mass spectrometric determination
T. Yarita; T. Otake; Y. Aoyagi; T. Kuroiwa; M. Numata; A. Takatsu, 筆頭著者, Proficiency testing (PT) for the determination of pesticide residues in soybean samples was organized by the National Metrology Institute of Japan (NMIJ). The candidate certified reference material, NMIJ CRM 7509-a, that was prepared from the raw soybeans containing target pesticides (diazinon, fenitrothion, chlorpyrifos, and permethrin) was used as the test sample. Forty participants submitted two sets of analytical results along with the details of the analytical method and conditions they applied. Two types of assigned values were established for each target pesticide: one was derived from the analytical results of the participants, and the other was provided from the analytical results by isotope-dilution mass spectrometry (IDMS). The latter values were 7.4-16% higher than the former values, plausibly because the analytical values from the IDMS measurements were not affected by the recovery ratio of the target pesticides during the analytical process. Thus, two kinds of z-scores were calculated for individual participants using the corresponding assigned values: one (z(1)-score) showed the relative performance score for the present PT and the other (z(2)-score) could be used for evaluation of the trueness of their analytical methods. (C) 2014 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Talanta, 2015年01月, ［査読有り］

Development of a certified reference material for the determination of perfluorooctanoic acid
N. Hanari; T. Yamazaki; N. Itoh; T. Yarita; N. Fujiki; R. Iwasawa; Y. Aoyagi; M. Numata, A certified reference material (CRM) for the determination of perfluorooctanoic acid (PFOA) has been issued as NMIJ CRM 4056-a by the National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ/AIST). Purity (kg kg(-1)) based on a titration method was determined by subtracting the mass fractions of impurities measured using liquid chromatography/mass spectrometry (LC/MS) from those of acids expressed as PFOA measured by a neutralization potentiometric titration. To validate an obtained result, purity based on a mass balance method was determined by subtracting the mass fractions of impurities, measured using LC/MS, Karl-Fischer titration (KFT), and vacuum evaporation, from 1 kg kg(-1). Results from both titration and mass balance methods were in agreement within the accepted limits of uncertainty. The certified purity of NMIJ CRM 4056-a was determined to be 0.959 kg kg(-1), calculated as the mean of the results obtained with the two methods. The standard uncertainty of the certified purity was evaluated from purity evaluations as well as from sample homogeneity and stability obtained from LC/MS and KFT analyses. Consequently, the expanded uncertainty was estimated to be 0.005 kg kg(-1) with a coverage factor of k = 2., SPRINGER
Accred. Qual. Assur., 2014年10月, ［査読有り］

Development of soybean certified reference material for pesticide residue analysis
T. Yarita; T. Otake; Y. Aoyagi; Y. Kuroda; M. Numata; H. Iwata; M. Watai; H. Mitsuda; T. Fujikawa; H. Ota, 筆頭著者, A soybean certified reference material for pesticide residue analysis was developed by the National Metrology Institute of Japan. Three organophosphorus (diazinon, fenitrothion, chlorphyrifos) and one pyrethroid (permethrin) pesticides were sprayed on soybeans three times before harvest. These soybeans were freeze pulverized, homogenized, bottled, and sterilized by gamma-irradiation to prepare the candidate material. Three isotope-dilution mass spectrometric methods that varied in terms of the solvents used for extraction of the target pesticides, the clean-up procedure, and the injection techniques and columns used for quantification via gas chromatography/mass spectrometry were applied to the characterization. Each target pesticide was quantified by two of these analytical methods, and the results were in good agreement. Homogeneity and stability assessment of the material demonstrated that the relative standard uncertainties due to the inhomogeneity and the instability for an expiry date of 55 months were 1.89-4.00% and 6.65-11.5%, respectively. The certified pesticide concentrations with expanded uncertainties (coverage factor k=2, approximate 95% confidence interval) calculated using the results of the characterization and the homogeneity and stability assessment were 21.7 +/- 3.2 mu g/kg for diazinon, 88 +/- 21 mu g/kg for fenitrothion, 11.1 +/- 3.2 mu g/kg for chlorpyrifos, and 20.1 +/- 4.3 mu g/kg for permethrin (as the sum of the constituent isomers). (C) 2013 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Talanta, 2014年02月, ［査読有り］

Variation in concentration of perfluorooctanoic acid in methanol solutions during storage
N. Hanari; N. Itoh; K. Ishikawa; T. Yarita; M. Numata, Perfluoroalkyl carboxylic acids (PFCAs) including perfluorooctanoic acid (PFOA) have been widely recognized as persistent environmental contaminants. For accurate quantification of PFCAs, their stability in calibration solutions is important because they are criteria of quantification. To examine stability of PFCAs in methanol, we monitored PFOA and its related compounds around 4 years. Interestingly, perfluorooctanoate was varied randomly, and methyl perfluorooctanoate (MePFOA) and methyl formate were observed when perfluorooctanoate decreased. Moreover, no detection of both methyl esters was in methanol solutions immediately after preparation. In each of prepared methanol solution of perfluorohexanoic, perfluoroheptanoic, and perfluorononanoic acids, their corresponding methyl esters and methyl formate were observed. Furthermore, MePFOA was observed even in the solutions stored around 4 months and thereafter MePFOA increased with increase in methyl formate. Therefore, PFCAs including PFOA should be used immediately after preparation when methanol is used as a solvent. (C) 2013 Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
Chemosohere, 2014年01月, ［査読有り］

Evaluation of the performance of 57 Japanese participating laboratories by two types of z-scores in proficiency test for the quantification of pesticide residues in brown rice
T. Otake; T. Yarita; Y. Aoyagi; M. Numata; A. Takatsu, A proficiency test for the analysis of pesticide residues in brown rice was carried out to support upgrading in analytical skills of participant laboratories. Brown rice containing three target pesticides (etofenprox, fenitrothion, and isoprothiolane) was used as the test samples. The test samples were distributed to the 57 participants and analyzed by appropriate analytical methods chosen by each participant. It was shown that there was no significant difference among the reported values obtained by different types of analytical method. The analytical results obtained by National Metrology Institute of Japan (NMIJ) were 3 % to 10 % greater than those obtained by participants. The results reported by the participant were evaluated by using two types of z-scores, that is, one was the score based on the consensus values calculated from the analytical results of participants, and the other one was the score based on the reference values obtained by NMIJ with high reliability. Acceptable z-scores based on the consensus values and NMIJ reference values were achieved by 87 % to 89 % and 79 % to 94 % of the participants, respectively. [Figure not available: see fulltext.], Springer Verlag
Anal. Bioanal. Chem., 2014年, ［査読有り］

Certified calibration solution reference material for the determination of perfluorooctane sulfonate from the National Metrology Institute of Japan (NMIJ)
N. Hanari; N. Itoh; K. Ishikawa; R. Iwasawa; Y. Aoyagi; T. Yarita; M. Numata, A new calibration solution reference material for the determination of perfluorooctane sulfonate anion (PFOS) and its salts has been issued as a certified reference material (CRM) by the National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ/AIST). The purity amount-of-substance fraction of raw material potassium perfluorooctane sulfonate (K-PFOS) was evaluated based on the results obtained using the freezing point depression method, and the purity mass fraction of the raw material was calculated using the average molar mass of impurities, the molar mass of K-PFOS, and the purity amount-of-substance fraction. The certified concentration of this CRM was obtained by multiplying the dilution ratio of the raw material in a prepared solution (methanol) determined from the gravimetric blending method by the purity of the raw material. The preparation concentration of K-PFOS as a certified value of NMIJ CRM 4220-a was determined to be 9.93mgkg(-1). In addition, the standard uncertainty of the certified value was evaluated from the purity evaluation as well as from sample inhomogeneity, instability, and preparation variation obtained from LC/MS measurements of different gravimetrically prepared solutions of the NMIJ CRM. Consequently, the expanded uncertainty was estimated to be 0.15mgkg(-1) with a coverage factor k=2 corresponding to the half-width of estimated confidence interval of approximately 95%., TAYLOR & FRANCIS LTD
Int. J. Environ. Anal. Chem., 2013年05月, ［査読有り］

Separation of parabens on a zirconia-based stationary phase in superheated water chromatography
T. Yarita; Y. Aoyagi; H. Sasai; A. Nishigaki; M. Shibukawa, 筆頭著者, A superheated water chromatography (SWC) method for the separation of alkyl esters of 4-hydroxybenzoic acid (parabens) using a zirconia-based stationary phase was developed and applied to real sample analysis. First, the SWC system was optimized in terms of the proper length of the preheating coil for establishing thermal equilibration of the mobile phase entering the column at the oven temperature. Next, the effect of the column temperature on the retention was investigated at 100 - 180 degrees C. The elution time for all parabens decreased with increasing column temperature, and linear relationships between in k and 1/T were obtained. At higher column temperatures, the elution time was further shortened because of the increased mobile-phase flow rate. Nevertheless, the loss of column efficiency at the higher flow rates was not significant. The application of the present method to the analysis of commercial lotions was then demonstrated. The quantification results obtained from SWC showed good agreement with those from a conventional HPLC method., JAPAN SOC ANALYTICAL CHEMISTRY
Anal. Sci., 2013年02月, ［査読有り］

Development of apple certified reference material for quantification of organophosphorus and pyrethroid pesticides　　　　　　　　　　　　　　　
T. Otake; T. Yarita; Y. Aoyagi; Y. Kuroda; M. Numata; H. Iwata; M. Watai; H. Mitsuda; T. Fujikawa; H. Ota, Elsevier
Food Chem., 2012年09月, ［査読有り］

Production and characterization of crop certified reference materials for pesticide residue analysis　　　　　　　　　　　　　　　
T. Yarita; T. Otake; Y. Aoyagi; Y. Kuroda; M. Numata, 筆頭著者
Proceedings of the 4th international symposium on pesticides and environmental safety, 2012年09月

Evaluation of pressurized liquid extraction for determination of organophosphorus and pyrethroid pesticides in soybean
T. Yarita; Y. Aoyagi; T. Otake, 筆頭著者, The purpose of this study was to develop an analytical method for the determination of organophosphorus and pyrethroid pesticides in soybean by pressurized liquid extraction (PLE). Two organic solvents, acetone and acetonitrile, were evaluated as extraction solvents. In both cases, the amount of extract was enhanced with increasing extraction temperature. The extracts obtained using acetonitrile were measured by gas chromatography/mass spectrometry after a cleanup process based on the analytical method for the Japanese Positive List System for Agricultural Chemicals Remaining in Foods. The effect of extraction temperature (range: 40-130 degrees C) on extraction efficiency was evaluated by a recovery study using 21 organophosphorus pesticides and 10 pyrethroid pesticides as target analytes and acetonitrile as the solvent. The results indicated that at 130 degrees C, some organophosphorus pesticides might be degraded, whereas extraction temperatures between 70 degrees C and 100 degrees C were optimal. Next, a prepared sample containing fenitrothion and permethrin was analyzed. Although the sample was not soaked in water prior to analysis, PLE provided analytical results comparable to those obtained by solvent extraction with homogenization. Therefore, PLE is considered a simple and alternative technique for the extraction of organophosphorus and pyrethroid pesticides in soybean., Taylor & Francis
J. Environ. Sci. Health B, 2012年08月, ［査読有り］

Evaluation of microwave-assisted extraction for the analysis of organophosphorus and pyrethroid pesticides in green onion
T. Otake; Y. Kuroda; Y. Aoyagi; T. Yarita, ラスト(シニア)オーサー, The aim of this study was to evaluate the efficiency of microwave-assisted extraction (MAE) for the analysis of organophosphorus (OP) and pyrethroid (PYR) pesticides in green onions by GC/MS. We optimized MAE extraction solvent, temperature, and time by using a certified reference material. As a result, the concentrations of two OP and two PYR target pesticides obtained by MAE with acetonitrile at 110 degrees C for 10 min were in good agreement with certified concentrations and comparable to the results by homogenization used as reference extraction technique. When the recovery test, performed by spiking the target pesticides into blank samples (5.0 g), was carried out with our optimized MAE conditions, mean recoveries of 16 OP and 10 PYR pesticides were 72-108% for a 1.0 mu g spiking level and 70-119% for a 0.2 mu g level. These results were acceptable according to the validation guideline for testing method of agricultural chemicals in food by Ministry of Health, Labour, and Welfare in Japan. The results suggested that MAE can be used for the analysis of OP and PYR pesticides in green onions., AOAC INT
J. AOAC Int., 2012年01月, ［査読有り］

Evaluation of the thermal effect on separation selectivity in anion-exchange processes using superheated water ion-exchange chromatography
M. Shibukawa; A. Taguchi; Y. Suzuki; K. Saitoh; T. Hiaki; T. Yarita, ラスト(シニア)オーサー, The thermal effect on retention and separation selectivity of inorganic anions and aromatic sulfonate ions in anion-exchange chromatography is studied on a quaternized styrene-divinylbenzene copolymer anion-exchange column in the temperature range of 40-120 degrees C using superheated water chromatography. The selectivity coefficient for a pair of identically charged anions approaches unity as temperature increases provided the ions have the same effective size, such that the retention of an analyte ion decreases with an increase in temperature when the analyte ion has stronger affinity for the ion-exchanger than that of the eluent counterion, whereas it increases when it has weaker affinity. The change in anion-exchange selectivity with temperature observed with superheated water chromatography has been discussed on the basis of the effect of temperature on hydration of the ions. At elevated temperatures, especially in superheated water, the electrostatic interaction or association of the ions with the fixed ion in the resin phase becomes a predominant factor resulting in a different separation selectivity from that obtained at ambient temperature., ROYAL SOC CHEMISTRY
Analyst, 2012年, ［査読有り］

計量法校正事業者登録制度用アルキルフェノール基準物質の差数法による純度評価　　　　　　　　　　　　　　　
羽成修康; 石川啓一郎; 鎗田孝; 大塚聡子; 岩澤良子; 藤木直美; 沼田雅彦, 日本分析化学会
分析化学, 2011年11月, ［査読有り］

Development of green onion and cabbage certified reference materials for quantification of organophosphorus and pyrethroid pesticides　　　　　　　　　　　　　　　
T. Otake; T. Yarita; Y. Aoyagi; Y. Kuroda; M. Numata; H. Iwata; K. Mizukoshi; M. Nakamura; M. Watai; H. Mitsuda; T. Fujikawa; H. Ota, Am. Chem. Soc.
J. Agr. Food Chem., 2011年07月, ［査読有り］

Accurate quantification of polycyclic aromatic hydrocarbons in dust samples using microwave-assisted solvent extraction combined with isotope-dilution mass spectrometry　　　　　　　　　　　　　　　
N. Itoh; A. Fushimi; T. Yarita; Y. Aoyagi; M. Numata, Elsevier
Anal. Chim. Acta, 2011年07月, ［査読有り］

Mass balance method for purity assay of phthalic acid esters: development of primary reference materials as traceability sources in the Japan Calibration Service System
K. Ishikawa; N. Hanari; Y. Shimizu; T. Ihara; A. Nomura; M. Numata; T. Yarita; K. Kato; K. Chiba, Purity assay of high-purity materials (HPMs) of phthalic acid esters (PAEs) was carried out by means of a mass balance method. In this method, chromatographic methods such as gas chromatography-flame ionization detector (GC-FID) and/or high-performance liquid chromatography (HPLC) in combination with other methods such as Karl-Fischer (KF) titration and vacuum evaporation (VE) were applied. The sum of the impurities estimated by these methods allowed the estimation of the purity of the main component by difference. Seven PAEs with varying side chain structures and levels of impurities were analysed on a systematic way in which impurities were classified into several groups in terms of their abundance, availability of qualitative information and availability of authentic compounds, etc. The absolute quantity of each impurity was determined by GC-FID and/or HPLC based on the calibration made by the authentic compounds of impurities whenever available. The purities in mass fraction of these PAEs were certified at the National Metrology Institute of Japan (NMIJ), and the PAEs were registered as primary reference materials playing an essential role in linking the metrological traceability of the Japan Calibration Service System (JCSS) to the International System of Units (SI)., SPRINGER
Accred. Qual. Assur., 2011年06月, ［査読有り］

Water content variation of p-n-heptylphenol reference material
N. Hanari; R. Iwasawa; S. Otsuka; N. Fujiki; A. Matsumoto; T. Ihara; K. Ishikawa; T. Yarita, ラスト(シニア)オーサー, Water content variation of candidate p-n-heptylphenol (HP) reference material (ampoule form) for preparation of a primary standard solution based on the Japan Calibration Service System, a national standards dissemination system, under the Measurement Law of Japan, was examined by a Karl-Fischer water content meter. As prepared samples, liquid-phase HP and upper, middle, and lower layers of solid-phase HP were measured since characteristic phase transition occurs near room temperature (melting point: 28.98 A degrees C). As a result of water content in liquid- and solid-phase HP, water content variation among three layers of solid-phase is found in within ampoules, though water content variation of liquid-phase is not found. Between-ampoule variation of water content is also found using total ampoules of liquid-phase HP used to eliminate within-ampoule variation. Moreover, water content variation is secondarily confirmed by the results of the amount-of-substance fraction of HP based on a differential scanning calorimeter. From these results in this study, it is concluded that within- and between-ampoule variations of water content may depend on phase transition and water loss during ampouling of candidate reference material, respectively., SPRINGER
Accred. Qual. Assur., 2010年12月, ［査読有り］

Characterization of certified reference material for quantification of polychlorinated biphenyls and organochlorine pesticides in fish
T. Otake; Y. Aoyagi; T. Yarita; M. Numata, Fish certified reference material (CRM), NMIJ CRM 7404-a, for the analysis of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) was developed by the National Metrology Institute of Japan, part of the National Institute of Advanced Industrial Science and Technology. Fish samples (Japanese seabass) used for the preparation of the CRM were collected from Tokyo Bay, and the edible part was freeze-dried, pulverized, sieved, homogenized, and sterilized by gamma-irradiation. This sample is in the form of a powder comprising approximately 10 g stored in a brown glass bottle. The certification was carried out using multiple analytical methods such as pressurized liquid extraction, Soxhlet extraction, saponification, and homogenization to ensure the reliability of analytical results; the certified values of target PCBs (PCB 28, PCB 70, PCB 105, PCB 153, and PCB 170) and OCPs (trans-nonachlor, dieldrin, p,p'-DDE, p,p'-DDT, and p,p'-DDD) were 1.05-14.0 mu g kg(-1) and 1.57-18.0 mu g kg(-1) for PCBs and OCPs, respectively. This is the first fish powder CRM in which PCBs and OCPs were determined by isotope dilution mass spectrometry., SPRINGER HEIDELBERG
Anal. Bioanal. Chem., 2010年07月, ［査読有り］

Superheated water ion-exchange chromatography: an experimental approach for interpretation of separation selectivity in ion-exchange process
M. Shibukawa; T. Shimasaki; T. Saito; T. Yarita, ラスト(シニア)オーサー, Cation-exchange selectivity for alkali and alkaline-earth metal ions and tetraalkylammonium ions on a strongly acidic sulfonic acid cation-exchange resin has been investigated in the temperature range of 40-175 degrees C using superheated water chromatography. Dependence of the distribution coefficient (In K(D)) on the reciprocal of temperature (1/T) is not linear for most of the ions studied, and the selectivity coefficient for a pair of alkali metal ions or that of alkaline-earth metal ions approaches unity as temperature increases. On the other hand, the retention order of tetraalkylammonium ions is reversed at 1.60 degrees C or above when eluted with Na(2)SO(4) aqueous solution and the larger ions are eluted faster than the smaller ones contrary to the retention order obtained at ambient temperature. The change in ion-exchange selectivity with temperature observed with superheated water chromatography has been discussed on the basis of the effect of temperature on hydration of the ions and specific adsorption or distribution of ionic species between the external solution and ion-exchange resin. In superheated water, the electrostatic interaction or association of the ions with the fixed ion becomes a predominant mechanism resulting in different separation selectivity from that obtained at ambient temperature., Am. Chem. Soc.
Anal. Chem., 2009年10月, ［査読有り］

Determination of phosphorus using capillary electrophoresis and micro-high-performance liquid chromatography hyphenated with inductively coupled plasma mass spectrometry for the quantification of nucleotides
S. Fujii; K. Inagaki; A. Takatsu; T. Yarita; K. Chiba, We performed the quantification of phosphorus in deoxynucleotides using capillary electrophoresis (CE) and micro-HPLC (mu HPLC) hyphenated with inductively coupled plasma mass spectrometry (ICP-MS) DNA and its component units have conventionally been determined by photometry, however, more selective and sensitive methods are needed for small biological samples CE and mu HPLC offer the advantages of good separation and small consumption of samples. and ICP-MS is a highly sensitive technique for the determination of a chemical element Therefore, we have developed an interface device for combining CE and mu HPLC with ICP-MS for quantifying nucleotides based on phosphorus content. The interface utilizes 4.5 mu L/min for nebulizing and effective introduction of the sample into ICP The samples of nucleotides and free phosphoric acid were well separated in the CE-ICP-MS measurement, and the calibration Curves (1-100 mu g/mL of the nucleotides showed a linear(R(2) > 0.999)increase in intensity Similarly, the samples of nucleotides were baseline separated using mu HPLC-ICP-MS, and the calibration cut were linear (R(2) > 0 998). The detection limits of these species and phosphorus in nucleotides using CE-ICP-MS and mu HPLC-ICP-MS were 0.77-6.5 ng/mL and 4.0-6.5 ng/mL, respectively These values were about one or two orders lower than those in a previous report. The sample volumes of these experiments were calculated to be about 10 nL and 50 nL per analysis. Therefore, these analytical methods have the potential to be useful for the determination of biological samples, Such as DNA and RNA molecules. (C) 2009 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
J. Chromatogr. A, 2009年10月, ［査読有り］

Development of certified reference material for quantification of two pesticides in brown rice
T. Otake; N. Itoh; Y. Aoyagi; M. Matsuo; N. Hanari; S. Otsuka; T. Yarita, ラスト(シニア)オーサー, Brown rice powder certified reference material, NMIJ CRM 7504-a, for the analysis of pesticide residues was developed by the National Metrology Institute of Japan, part of the National Institute of Advanced Industrial Science and Technology. Brown rice sample was harvested to contain the pesticides such as etofenprox and fenitrothion, and that was collected from a field in Ibaraki Prefecture in Japan. The certification was carried out using multiple analytical methods such as pressurized liquid extraction, homogenization, and solid-liquid extraction (shaking); the values of target pesticides were obtained by isotope dilution mass spectrometry. Certified values were 0.19 +/- 0.05 mg/kg and 0.109 +/- 0.017 mg/kg for etofenprox and fenitrothion, respectively., AMER CHEMICAL SOC
J. Agr. Food Chem., 2009年09月, ［査読有り］

Certified reference materials for determination of phthalates and alkylphenols from the National Metrology Institute of Japan　　　　　　　　　　　　　　　
N. Hanari; K. Ishikawa; Y. Shimizu; R. Iwasawa; S. Otsuka; N. Fujiki; X Bao; T. Yarita; K. Kato; N. Yamashita, Internal. Symp. Halogenated Persistent Org. Poll.
Organohalogen Compds., 2009年08月

同位体希釈－誘導結合プラズマ質量分析法による底質中微量元素の全量及び化学形態別分析
稲垣和三; 高津章子; 鎗田孝; 岡本研作; 千葉光一, Isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) is one of the reliable methods for total and species-specific quantitative analysis of trace elements. However, several technical problems (e.g. spectral interference caused from sample constituents) should be overcome to obtain reliable analytical results when environmental samples are analyzed by ID-ICP-MS. In our laboratory, various methods based on ID-ICP-MS have been investigated for reliable quantitative analyses of trace elements in environmental samples. In this paper, coprecipitate separation/ID-ICP-MS for the determination of trace elements in sediment, cation exchange disk filtration/ID-ICP-MS for the determination of selenium in sediment, species-specific ID-ICP-MS using (118)Sn-labeled organotin compounds for the determination of butyltins and phenyltins, and the application of the ID-ICP-MS methods to the certification of sediment reference materials are described., JAPAN SOC ANALYTICAL CHEMISTRY
分析化学, 2009年04月, ［査読有り］

Certified reference material for quantification of polycyclic aromatic hydrocarbons in sediment from the National Metrology Institute of Japan
Nobuyasu Itoh; Yoshie Aoyagi; Akiko Takatsu; Takashi Yarita, The National Metrology Institute of Japan has issued a certified reference material (CRM) of freshwater lake sediment for polycyclic aromatic hydrocarbon (PAHs) analyses. The certification used three extraction techniques: pressurized liquid extraction (PLE) with toluene, PLE with dichloromethane/ethyl acetate (1:1 by volume), and alkaline extraction (1 M KOH in methanol) in combination with microwave-assisted extraction. Both gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/dopant-assisted atmospheric pressure photoionization/MS (LC/DA-APPI/MS) analyses were used. Certified values are provided for 18 PAHs at 1-25 mu g kg(-1) except for perylene (2.08 x 10(3) mu g kg(-1)), and information values are provided for two. Since the values of PAHs in the CRM are much lower than those in other CRMs and are comparable to those found at sites with little human influence, the CRM is suitable for PAH monitoring in sediment and soil samples., SPRINGER HEIDELBERG
ANALYTICAL AND BIOANALYTICAL CHEMISTRY, 2009年04月, ［査読有り］

MECHANISM OF IONIZATION OF POLYCYCLIC AROMATIC HYDROCARBONS BY A TOLUENE/ANISOLE MIXTURE AS A DOPANT IN LIQUID CHROMATOGRAPHY/DOPANT-ASSISTED ATMOSPHERIC-PRESSURE PHOTOIONIZATION/MASS SPECTROMETRY
Nobuyasu Itoh; Tomohiro Narukawa; Masahiko Numata; Yoshie Aoyagi; Takashi Yarita; Akiko Takatsu, Ionization mechanisms of 16 polycyclic aromatic hydrocarbons (PAHs) by dopant-assisted atmospheric-pressure photoionization (DA-APPI) with a toluene/anisole mixture as a dopant were examined in the reversed-phase liquid chromatography mode with a methanol/water to acetonitrile linear gradient mobile phase. When toluene/anisole mixtures were used as dopants, their characteristics were governed by anisole. Since the IE of anisole (8.20 eV) is below that of toluene (8.83 eV), anisole is ionized not only by photons from the krypton lamp but also by charge transfer from toluene radical cations. In the latter half of chromatogram, when acetonitrile was dominant in the eluent, ions originating from both toluene and anisole decreased while acetonitrile-cluster ions began to increase. Because acetonitrile-cluster ions are not formed with anisole alone, but are formed with toluene alone, toluene radical cations would be consumed to form acetonitrile-cluster ions., TAYLOR & FRANCIS LTD
POLYCYCLIC AROMATIC COMPOUNDS, 2009年, ［査読有り］

Fragmentation of a non-ester pyrethroid insecticide by atmospheric pressure chemical ionization　　　　　　　　　　　　　　　
N. Itoh; T. Kinumi; M. Inagaki; T. Yarita, ラスト(シニア)オーサー, IM Publication
Eur. J. Mass Spectrom., 2009年01月, ［査読有り］

Multiresidue analysis and monitoring of pesticides in rice by pressurized liquid extraction
Takamitsu Otake; Yoshie Aoyagi; Takashi Yarita, The aim of this study was to assess the performance of a method of analyzing pesticides in rice by using pressurized liquid extraction (PLE) and to perform a preliminary monitoring by using that method. The instrumental quantification limit, instrumental detection limit, method quantification limit, and method detection limit were determined. PLE temperature was also optimized for 6 target pesticides. Mean recoveries of spiked rice with target pesticides (4 ng/g and 40 ng/g) were 83%-109% with the repeatability of the analysis, represented as relative standard deviations, ranged from 1.3% to 11% (n = 5) for PLE at 130 degrees C. These results were satisfactory according to the method of positive list in Japan. In a preliminary analysis of 10 target pesticides in 54 commercial rice samples, ferimzone was detected in only one unpolished rice sample., TAYLOR & FRANCIS INC
JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART B-PESTICIDES FOOD CONTAMINANTS AND AGRICULTURAL WASTES, 2009年, ［査読有り］

Application of pesticide quantification in unpolished rice by LC-dopant-assisted atmospheric pressure photoionization-MS
Nobuyasu Itoh; Takamitsu Otake; Yoshie Aoyagi; Mayumi Matsuo; Takashi Yarita, We applied liquid chromatography-dopant-assisted atmospheric pressure photoionizationmass spectrometry to quantify four distinct pesticides (isoprothiolane, fenitrothion, fthalide, and ethophenprox) in unpolished rice flour. Although the effect of acetone as a dopant on enhancement of ionization differed among the pesticides, the analytical results by LC-DAAPPI-MS with a dopant flow rate of 50 lL min-1 were not only repeatable (relative SD <
9%, n = 3) but also comparable to those by gas chromatography-mass spectrometry. © 2009 Vieweg+Teubner | GWV Fachverlage GmbH., Friedr. Vieweg und Sohn Verlags GmbH
Chromatographia, 2009年, ［査読有り］

Evaluation of microwave-assisted extraction for the analysis of polychlorinated biphenyls and organochlorine pesticides in fish　　　　　　　　　　　　　　　
T. Otake; Y. Aoyagi; M. Numata; T. Yarita, ラスト(シニア)オーサー, AOAC Int.
J. AOAC Int., 2008年11月, ［査読有り］

Calcium tungstate coprecipitation for removal of Sr interference with determination of Rb by ID-ICP-MS　　　　　　　　　　　　　　　
Y. Zhu; K. Inagaki; T. Yarita; K. Chiba, Elsevier
Talanta, 2008年10月, ［査読有り］

Preparation of a sulfoxide group and ammonium salt-bonded silica stationary phase for separation of polychlorinated biphenyls from mineral oils
M. Numata; T. Kaneko; Q. Mi; M. Ye; T. Kawamata; M. Matsuo; T. Yarita, ラスト(シニア)オーサー, Elsevier
J. Chromatogr. A, 2008年10月, ［査読有り］

Development of saw palmetto (Serenoa repens) fruit and extract standard reference materials
Michele M. Schantz; Mary Bedner; Stephen E. Long; John L. Molloy; Karen E. Murphy; Barbara J. Porter; Karsten Putzbach; Catherine A. Rimmer; Lane C. Sander; Katherine E. Sharpless; Jeanice B. Thomas; Stephen A. Wise; Laura J. Wood; James H. Yen; Takashi Yarita; Agnes NguyenPho; Wendy R. Sorenson; Joseph M. Betz, As part of a collaboration with the National Institutes of Health's Office of Dietary Supplements and the Food and Drug Administration's Center for Drug Evaluation and Research, the National Institute of Standards and Technology has developed two standard reference materials (SRMs) representing different forms of saw palmetto (Serenoa repens), SRM 3250 Serenoa repens fruit and SRM 3251 Serenoa repens extract. Both of these SRMs have been characterized for their fatty acid and phytosterol content. The fatty acid concentration values are based on results from gas chromatography with flame ionization detection (GC-FID) and mass spectrometry (GC/MS) analysis while the sterol concentration values are based on results from GC-FID and liquid chromatography with mass spectrometry analysis. In addition, SRM 3250 has been characterized for lead content, and SRM 3251 has been characterized for the content of beta-carotene and tocopherols. SRM 3250 (fruit) has certified concentration values for three phytosterols, 14 fatty acids as triglycerides, and lead along with reference concentration values for four fatty acids as triglycerides and 16 free fatty acids. SRM 3251 (extract) has certified concentration values for three phytosterols, 17 fatty acids as triglycerides, beta-carotene, and gamma-tocopherol along with reference concentration values for three fatty acids as triglycerides, 17 fatty acids as free fatty acids, beta-carotene isomers, and delta-tocopherol and information values for two phytosterols. These SRMs will complement other reference materials currently available with concentrations for similar analytes and are part of a series of SRMs being developed for dietary supplements., SPRINGER HEIDELBERG
ANALYTICAL AND BIOANALYTICAL CHEMISTRY, 2008年10月, ［査読有り］

Accurate quantification of polycyclic aromatic hydrocarbons in environmental samples using deuterium-labeled compounds as internal standards
Nobuyasu Itoh; Masahiko Numata; Yoshie Aoyagi; Takashi Yarita, For the accurate quantification of polycyclic aromatic hydrocarbons (PAHs) in environmental samples by isotope-dilution mass spectrometry (IDMS) and gas chromatography-mass spectrometry (GC-MS), we used deuterium-labeled PAHs (D-PAHs) as internal standards for mu g g(-1)-level certified reference materials and corresponding calibration solutions. Although pressurized liquid extraction (PLE) causes significant biases in the analytical results for ng g(-1)-level samples (2.4 - 15%), biases in the analytical results by PLE (190 degrees C, 20 MPa, 2 cycles) were small (<2.3%) and negligible for mu g g(-1)-level samples when expanded uncertainty (coverage factor k = 2) was considered., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, 2008年09月, ［査読有り］

Differences in the yields of polycyclic aromatic hydrocarbons by pressurized liquid extraction and the Japanese official method
Nobuyasu Itoh; Takamitsu Otake; Masahiko Numata; Yoshie Aoyagi; Mayumi Matsuo; Takashi Yarita, To improve the extraction of polycyclic aromatic hydrocarbons (PAHs) from sediment samples, we optimized the conditions of pressurized liquid extraction (PLE). The yields increased as the extraction temperature increased from 100 to 190 degrees C, but the effect of increasing pressure (from 15 to 20 MPa) was small. Parameters of 190 degrees C and 20 MPa, near the maximum of the equipment, gave the highest yield. Under these conditions, the yields of 17 PAHs were 1.5-34 times those obtained by the Japanese official method (shaking and ultrasonic extraction with acetone at room temperature)., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, 2008年09月, ［査読有り］

Certification of methylmercury in fish tissue reference materials by species-specific isotope dilution mass spectrometric analysis　　　　　　　　　　　　　　　
K. Inagaki; T. Kuroiwa; T. Narukawa; T. Yarita; A. Takatsu; K. Okamoto; K. Chiba, Springer
Anal. Bioanal. Chem., 2008年08月, ［査読有り］

Certified reference materials for determination of p-n-nonylphenol and p-n-heptylphenol form the National Metrology Institute of Japan　　　　　　　　　　　　　　　
N. Hanari; K. Ishikawa; Y. Shimizu; R. Iwasawa; S. Otsuka; T. Yarita, ラスト(シニア)オーサー, Internal. Symp. Halogenated Persistent Org. Poll.
Organohalogen Compds., 2008年08月

Preparation and characterization of organic calibration solutions for development of certified reference materials at the National Metrology Institute of Japan
K. Ishikawa; N. Hanari; Y. Shimizu; T. Ihara; T. Maeda; A. Nomura; T. Yarita; K. Kato; K. Chiba, Certified reference materials (CRMs) are playing an increasingly important role in environmental monitoring in Japan. The National Metrology Institute of Japan (NMIJ)/National Institute of Advanced Industrial Science and Technology (AIST) has been developing CRMs of organic calibration solutions since 2003, and has issued several NMIJ CRMs. The development of these materials was conducted at the NMIJ in cooperation with candidate material producers. The freezing-point depression method was principally adopted for assessment of the purity of starting materials to give reliable certified values. Gas chromatography with flame ionization detection (GC-FID) and/or high-performance liquid chromatography (HPLC), which are based on independent principles and whose levels of accuracy are well evaluated, were applied in combination with other methods to avoid any possible analytical bias. Purity assessment is outlined for two typical examples, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDD) and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT), which were used as starting materials for a CRM under development. Methods adopted for gravimetric preparation and ampouling of solutions were qualified and optimized to reduce the uncertainties of certified values due to these factors. Furthermore, a new experimental scheme for assessment of stability and preparation variation is proposed for the proper estimation of uncertainties., SPRINGER
ACCREDITATION AND QUALITY ASSURANCE, 2008年07月, ［査読有り］

Mineral oil certified reference materials for the determination of polychlorinated biphenyls from the National Metrology Institute of Japan (NMIJ)
Masahiko Numata; Yoshie Aoyagi; Mayumi Matsuo; Keiichiro Ishikawa; Nobuyasu Hanari; Satoko Otsuka; Yoko Tsuda; Takashi Yarita, Four mineral oil certified reference materials (CRMs), NMIJ CRM 7902-a, CRM 7903-a, CRM 7904-a, and CRM 7905-a, have been issued by the National Metrology Institute of Japan, which is part of the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST), for the determination of polychlorinated biphenyls (PCBs). The raw materials for the CRMs were an insulation oil (CRM 7902-a and CRM 7903-a) and a fuel oil (CRM7904-a and CRM 7905-a). A solution of PCB3, PCB8, and technical PCB products, comprising four types of Kaneclor, was added to the oil matrices. The total PCB concentrations in the PCB-fortified oils (CRM 7902-a and CRM 7904-a) are approximately 6 mg kg(-1). In addition, the mineral oils which were not fortified with PCBs were also distributed as CRMs (CRM 7903-a and CRM 7905-a). Characterization of these CRMs was conducted by the NMIJ/AIST, where the mineral oils and the PCB solution were analyzed using multiple analytical methods such as dimethylsulfoxide extraction, normal-phase liquid chromatography, gel permeation chromatography, reversed-phase liquid chromatography, and chromatography using sulfoxide-bonded silica; and/or various capillary columns for gas chromatography, and two ionization modes for mass spectrometry. The target compounds in the mineral oils and those in the PCB solution were determined by one of the primary methods of measurement, isotope dilution-mass spectrometry (ID-MS). Certified values have been provided for 11 PCB congeners (PCB3, 8, 28, 52, 101, 118, 138, 153, 180, 194, and 206) in the CRMs. These CRMs have information values for PCB homologue concentrations determined by using a Japanese official method for determination of PCBs in wastes and densities determined with an oscillational density meter. Because oil samples having arbitrary PCB concentrations between respective property values of the PCB-fortified and nonfortified CRMs can be prepared by gravimetric mixing of the CRM pairs, these CRMs can be used for validation of PCB analyses using various instruments which have different sensitivities., SPRINGER HEIDELBERG
ANALYTICAL AND BIOANALYTICAL CHEMISTRY, 2008年07月, ［査読有り］

Simultaneous determination of trimethyl- and triethyllead in urban dust by species-specific isotope dilution/gas chromatography-inductively coupled plasma mass spectrometry
Tomoki Yabutani; Junko Motonaka; Kazumi Inagaki; Akiko Takatsu; Takashi Yarita; Koichi Chiba, Both (206)Pb-labeled trimethyllead (TML) and triethyllead (TEL) were synthesized from (206)Pb-enriched metallic Pb certified reference material (NIST SRM 983) and iodomethane or iodoethane through a one-process reaction in a closed system using centrifuge tubes, respectively. Organolead compounds in an urban dust reference material (BCR CRM 605) were extracted with an acetic acid/methanol (1: 1) solution, which was mechanically shaken for 24 h. After adjusting the pH of the extracted solution to pH 5, the extracted organolead compounds were derivatized by tetrabutylammonium tetrabutylborate (TATB) and measured with GC-ICPMS. The analytical results of TML and TEL for BCR CRM 605 were 8.22 +/- 0.04 mu g kg(-1) (mean standard deviation, n = 3) and 1.12 +/- 0.06 mu g kg(-1), respectively. The analytical results of TML agreed well with the certified value (7.9 +/- 1.2 mu g kg(-1))., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, 2008年06月, ［査読有り］

精米粉末中カドミウム及び主要無機質の技能試験
進藤久美子; 塚越芳樹; 内藤成弘; 稲垣和三; 鎗田孝; 成川知弘; 千葉光一; 安井明美, 国際的な食品規格を作成するコーデックス委員会が定める精米中カドミウム基準値0.4mg/kg fw(fw:新鮮重当たり)の約半分のカドミウム0.2mg/kg dw(dw:乾物重当たり)をマトリックス中に含む精米粉末の候補標準物質を用いて,カドミウム及び主要無機質の技能試験を実施した.カドミウムの測定は必須としナトリウム,カリウム,マグネシウム,カルシウム,リン,鉄,亜鉛,銅及びマンガンの測定は任意とした.試料は59試験所に配付し,57試験所から59の測定結果が返送された.データ解析は,国際標準化団体であるIUPAC,IS0,AOAC Internationalが協力して2006年に改訂した技能試験に関するハーモナイズドプロトコルに従って行った.外れ値除去後の57個の測定値から求めたカドミウムの付与された値は0.189mg/kg dw,その拡張不確かさ(k=2)は0.004mg/kg dwであった.この付与された値は,候補標準物質のカドミウムの特性値0.195mg/kg dw,その拡張不確かさ(k=2)0.006 mg/kg dwと危険率5%で有意な差が認められなかった.技能試験データから求めた10元素の付与された値の相対不薙かさ0.8～2.3%は,候補標準物質の特性値の相対不確かさ1.5～2.0%とほぼ同じ範囲内であった.zスコアが-2から+2の範囲内の試験所の比率は,カドミウムが95‰マンガンが97%であったが,他の元素については90%未満であった.よって,zスコアが-2から+2の範囲外になり,分析法について自己点検すべき試験所は,どの元素にも存在したが,カドミウムとマンガン以外の元素について特にそのような試験所が多い結果が得られた., 日本分析化学会
分析化学, 2008年06月, ［査読有り］

Development of a highly precise ID-ICP-SFMS method for analysis of low concentrations of lead in rice flour reference materials　　　　　　　　　　　　　　　
Y. Zhu; K. Inagaki; T. Yarita; K. Chiba, Springer
Anal. Bioanal. Chem., 2008年05月, ［査読有り］

Alkaline extraction in combination with microwave-assisted extraction followed by solid-phase extraction treatment for polycyclic aromatic hydrocarbons in a sediment sample　　　　　　　　　　　　　　　
N. Itoh; M. Numata; T. Yarita, ラスト(シニア)オーサー, Elsevier
Anal. Chim. Acta, 2008年04月, ［査読有り］

Calibration of an evaporative light-scattering detector as a mass detector for supercritical fluid chromatography by using uniform poly(ethylene glycol) oligomers　　　　　　　　　　　　　　　
K. Takahashi; S. Matsuyama; T. Saito; H. Kato; S. Kinugasa; T. Yarita; T. Maeda; H. Kitazawa; M. Bonoshita, Elsevier
J. Chromatogr. A, 2008年04月, ［査読有り］

Comparison of low-level polycyclic aromatic hydrocarbons in sediment revealed by Soxhlet extraction, microwave-assisted extraction, and pressurized liquid extraction
Nobuyasu Itoh; Masahiko Numata; Yoshie Aoyagi; Takashi Yarita, We analyzed polycyclic aromatic hydrocarbons (PAHs) present in lake sediment at low levels (< 1 mu gg(-1)) by using Soxhlet extraction (Soxhlet), microwave -assisted extraction (MAE), and pressurized liquid extraction (PLE) in combination with gas chromatography and isotope-dilution mass spectrometry. Although all extraction techniques showed good repeatability for five target PAHs (relative standard deviation < 5.2%, n = 3), the results decreased in the order PLE > MAE > Soxhlet. Differences in the results originated mainly from differences in the extraction efficiencies of the techniques for native PAHs, because all techniques gave comparable recovery yields of corresponding C-13-labeled PAHs (C-13-PAHs) (51-84%). Since non-negligible amounts of both native PAHs and C-13-PAHs were re-adsorbed on matrix in MAE, not only recovery yields of C-13-PAHs but also efficiencies of extraction of native PAHs should be examined to evaluate the appropriateness of any analytical procedures. (C) 2008 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
ANALYTICA CHIMICA ACTA, 2008年03月, ［査読有り］

Preparation of sulfoxide residue bonded silica stationary phase for separation of polychlorinated biphenyls from mineral oils (vol 79, pg 9211, 2007)
Masahiko Numata; Yoshie Aoyagi; Yoko Tsuda; Takashi Yarita; Akiko Takatsu, AMER CHEMICAL SOC
ANALYTICAL CHEMISTRY, 2008年01月, ［査読有り］

Evaluation of pressurized liquid extraction for the analysis of four pesticides in unpolished rice
Takamitsu Otake; Yoshie Aoyagi; Mayumi Matsuo; Nobuyasu Itoh; Takashi Yarita, The aim of to evaluate efficiency of this study was extraction pressurized liquid extraction (PLE) for the analysis of four pesticides, fthalide, etofenprox, fenitrothion, and isoprothiolane, in unpolished rice by comparing with homogenization as a reference technique. The concentrations of four selected pesticides obtained by PLE with acetonitrile at 130 degrees C for 10 min x 2 cycles were comparable to those by homogenization with water-soaking. The repeatability of the analysis, represented as relative standard deviations (RSDs), were 1.4-3.6% (n = 3) for PLE at 130 degrees C and 1.2-3.8% (n = 3) for homogenization with water-soaking. Recovery yields of surrogates were 75-88% and 87-109% for PLE at 130 degrees C and homogenization with water-soaking, respectively, and these were satisfactory according to the method of positive list. This study suggested that PLE can be applied for the analysis of selected four pesticides in unpolished rice as well as homogenization with water-soaking., TAYLOR & FRANCIS INC
JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART B-PESTICIDES FOOD CONTAMINANTS AND AGRICULTURAL WASTES, 2008年, ［査読有り］

CERTIFIED CALIBRATION SOLUTION REFERENCE MATERIAL FOR THE DETERMINATION OF BENZO[A]PYRENE FROM THE NATIONAL METROLOGY INSTITUTE OF JAPAN (NMIJ)
N. Hanari; K. Ishikawa; S. Otsuka; K. Higuchi; R. Iwasawa; T. Yarita, A new calibration solution reference material (NMIJ CRM 4213-a) for benzo[a]pyrene (BaP) analysis was prepared and certified by the National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ/AIST). Certification of CRM 4213-a was carried out at NMIJ using a freezing point depression method and gravimetric preparation. Certified concentration of this CRM was obtained by multiplying the dilution ratio of raw material BaP in a prepared solution with purity of the raw material. Purity of our raw material was calibrated by a gas chromatograph with flame ionization detection using that of high-purity BaP purified by using a high performance liquid chromatograph with a normal phase column, because purity determination of the raw material by a differential scanning calorimeter (DSC) couldn't be assessed directly. The purity of high-purity BaP was assessed in the molar fraction by DSC, and then the purity of the mass fraction was calculated based on average molecular weight of impurities and the purity of the molar fraction. CRM 4213-a has been developed with a certified value of 99.2 mg/kg. Uncertainty was evaluated from purity assessment as well as homogeneity and stability of the CRM, and expanded uncertainty was estimated as 3.9 mg/kg with coverage factor k = 2, corresponding to an estimated confidence interval of approximately 95%., TAYLOR & FRANCIS LTD
POLYCYCLIC AROMATIC COMPOUNDS, 2008年, ［査読有り］

Preparation of sulfoxide residue bonded silica stationary phase for separation of polychlorinated biphenyls from mineral oils
Masahiko Numata; Yoshie Aoyagi; Yoko Tsuda; Takashi Yarita; Akiko Takatsu, In this study, a sulfoxide residue bonded silica stationary phase was prepared for the separation of polychlorinated biphenyls (PCBs) from mineral oils, and its properties were investigated. Organic sulfide was attached to a silica surface by an amide bond, and the bonded sulfide residues were oxidized to sulfoxide with hydrogen peroxide to afford sulfoxide and sulfone residues bonded to the stationary phases (0.84 and 0.63 mmol of sulfur bonded per gram, respectively). The oxidation states of sulfur atoms bonded on the stationary phases could be determined using high-resolution X-ray fluorescence spectra. The modified stationary phases, especially sulfoxide-bonded one, separated PCBs from mineral oils (paraffin-based transformer oils) more efficiently than aminopropyl silica or other polar stationary phases that have been used for the cleanup of PCBs. The chromatographic parameters for an aliphatic hydrocarbon (eicosane) and some PCB congeners indicated strong retention of highly chlorinated biphenyls by the sulfoxide-bonded silica compared with the aminopropyl silica. A cleanup procedure was established for simple determination of PCBs in mineral oil samples using the sulfoxide-bonded silica packed column fractionation. The analytical method was validated using a certified reference material and a PCB-fortified transformer oil sample., AMER CHEMICAL SOC
ANALYTICAL CHEMISTRY, 2007年12月, ［査読有り］

Evaluation of behavioral differences between native polycyclic aromatic hydrocarbons and C-13-labeled internal standards during clean-up steps of analysis
Nobuyasu Itoh; Masahiko Numata; Takashi Yarita, We confirmed that concentrations of polycyclic aromatic hydrocarbons (PAHs) obtained by isotope dilution mass spectrometry (IDMS) using the corresponding C-13-labeled internal standards are reliable even after clean-up steps. Change in the ratio of phenanthrene to C-13(6)-phenanthrene was less than 0.2%, although the recovery yield Of C-13(6)-phenanthrene decreased to 60%. Since changes in the ratios were commonly within the relative standard deviations of the concentrations (1.5 - 5.4%) obtained using gas chromatography-mass spectrometry in combination with pressurized-liquid extraction, concentrations obtained by IDMS with C-13-PAHs should be reliable., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, 2007年10月, ［査読有り］

termination of cadmium in grain by isotope dilution ICP-MS and coprecipitation using sample constituents as a carrier precipitant
K. Inagaki; T. Narukawa; T. Yarita; A. Takatsu; K. Okamoto; K. Chiba, A coprecipitation method using sample constituents as carrier precipitants was developed that can remove molybdenum, which interferes with the determination of cadmium in grain samples via isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). Samples were digested with HNO3, HF, and HClO4, and then purified 6 M sodium hydroxide solution was added to generate colloidal hydrolysis compounds, mainly magnesium hydroxide. Cadmium can be effectively separated from molybdenum because the cadmium forms hydroxides and adsorbs onto and/or is occluded in the colloid, while the molybdenum does not form hydroxides or adsorb onto the hydrolysis colloid. The colloid was separated by centrifugation and then dissolved with 0.2 M HNO3 solution to recover the cadmium. The recovery of Cd achieved using the coprecipitation was > 97%, and the removal efficiency of Mo was approximately 99.9%. An extremely low procedural blank (below the detection limit of ICPMS) was achieved by purifying the 6 M sodium hydroxide solution via Mg coprecipitation using Mg(NO3)(2) solution. The proposed method was applied to two certified reference materials (NIST SRM 1567a wheat flour and SRM 1568a rice flour) and CCQM-P64 soybean powder. Good analytical results with small uncertainties were obtained for all samples. This method is simple and reliable for the determination of Cd in grain samples by ID-ICPMS., Springer
Anal. Bioanal. Chem., 2007年10月, ［査読有り］

Preparation and certification of arsenobetaine reference material NMIJ CRM 7901-a
Tomohiro Narukawa; Koichi Chiba; Takayoshi Kuroiwa; Takashi Yarita; Akiko Takatsu, An arsenobetaine [ (CH3)(3)As+CH2COO-] solution reference material, NMIJ CRM 7901-a, intended for use in the speciation of arsenic compounds, was developed and certified by the National Metrology Institute of Japan (NMIJ), part of the National Institute of Advanced Industrial Science and Technology (AIST). The high-purity arsenobetaine powder was synthesized from trimethylarsine [ (CH3)(3)As], and it was dissolved in water in order to prepare 20 mg kg(-1)supercript stop of arsenobetaine standard solution. The solution was bottled in 500 bottles (each containing 10 ml). Certification of the CRM for arsenobetaine was conducted by NMIJ. The concentration of As was determined by four independent analytical techniques (ICP-MS, ICP-OES, GFAAS and LC-ICP-MS), and each result was converted to the arsenobetaine concentration by applying an appropriate factor. The arsenobetaine concentration in the CRM was thus certified., SPRINGER HEIDELBERG
ANALYTICAL AND BIOANALYTICAL CHEMISTRY, 2007年09月, ［査読有り］

Preparation and characterization of standard reference material 3276, carrot extract in oil
Katherine E. Sharpless; Jeanice Brown Thomas; David L. Duewer; Karsten Putzbach; Catherine A. Rimmer; Lane C. Sander; Michele M. Schantz; Stephen A. Wise; Takashi Yarita; James H. Yen, The National Institute of Standards and Technology (NIST), the Food and Drug Administration (FDA) Center for Drug Evaluation and Research (CDER) and Center for Food Safety and Applied Nutrition (CFSAN), and the National Institutes of Health (NIH), Office of Dietary Supplements (ODS) are collaborating to produce a series of standard reference materials (SRMs) for dietary supplements. Standard reference material (SRM) 3276 Carrot Extract in Oil is one in this series, with values assigned for trans-alpha-carotene, trans- and total beta-carotene, delta- and gamma-tocopherol, and twelve fatty acids. Results for carotenoids and tocopherols were obtained by use of combinations of liquid chromatography (LC), on columns of differing selectivity, with absorbance and mass spectrometric (MS) detection. Fluorescence detection also was used for the tocopherols. Results for fatty acids were obtained by use of gas chromatography (GC) with both flame-ionization and mass-spectrometric detection. This material is intended for use as a primary control material when assigning values to in-house (secondary) control materials and for validation of analytical methods for measurement of these analytes in similar matrices., SPRINGER HEIDELBERG
ANALYTICAL AND BIOANALYTICAL CHEMISTRY, 2007年09月, ［査読有り］

Matrix certified reference materials for determination of persistent organic pollutants from the National Metrology Institute of Japan (NMIJ)　　　　　　　　　　　　　　　
M. Numata; T. Yarita; K. Ishikawa; T. Ihara; N. Hanari; Y. Aoyagi; S. Otsuka; M. Matsuo; Y. Tsuda; M. Yamazaki; K. Kato; T. Maeda; T. Takatsu; K. Okamoto; K. Chiba, Internal. Symp. Halogenated Persistent Org. Poll.
Organohalogen Compds., 2007年09月

Sulfoxide residue-bonded silica stationary phases for separation of polychlorinated biphenyls from insulation oil　　　　　　　　　　　　　　　
M. Numata; T. Kaneko; Q. Mi; M. Ye; T. Kawamata; T. Otaka; T. Yarita, ラスト(シニア)オーサー, Internal. Symp. Halogenated Persistent Org. Poll.
Organohalogen Compds., 2007年09月

Certification of butyltins and phenyltins in marine sediment certified reference material by species-specific isotope-dilution mass spectrometric analysis using synthesized Sn-118-enriched organotin compounds
Kazumi Inagaki; Akiko Takatsu; Takuro Watanabe; Yoshie Aoyagi; Takashi Yarita; Kensaku Okamoto; Koichi Chiba, A new marine sediment certified reference material, NMIJ CRM 7306-a, for butyltin and phenyltin analysis has been prepared and certified by the National Metrological Institute of Japan at the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST). Candidate sediment material was collected at a bay near industrial activity in Japan. After air-drying, sieving, and mixing the material was sterilized with gamma-ray irradiation. The material was re-mixed and packaged into 250 glass bottles (15 g each) and these were stored in a freezer at -30 degrees C. Certification was performed by use of three different types of species-specific isotope-dilution mass spectrometry (SSID-MS)-SSID-GC-ICP-MS, SSID-GC-MS, and SSID-LC-ICP-MS, with Sn-118-enriched organotin compounds synthesized from Sn-118-enriched metal used as a spike. The Sn-118-enriched mono-butyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) were synthesized as a mixture whereas the Sn-118-enriched di-phenyltin (DPhT) and triphenyltin (TPhT) were synthesized individually. Four different extraction methods, mechanical shaking, ultrasonic, microwave-assisted, and pressurized liquid extraction, were adopted to avoid possible analytical bias caused by non-quantitative extraction and degradation or inter-conversion of analytes in sample preparations. Tropolone was used as chelating agent in all the extraction methods. Certified values are given for TBT 44 +/- 3 mu g kg(-1) as Sn, DBT 51 +/- 2 mu g kg(-1) as Sn, MBT 67 +/- 3 mu g kg(-1) as Sn, TPhT 6.9 +/- 1.2 mu g kg(-1) as Sn, and DPhT 3.4 +/- 1.2 mu g kg(-1) as Sn. These levels are lower than in other sediment CRMs currently available for analysis of organotin compounds., SPRINGER HEIDELBERG
ANALYTICAL AND BIOANALYTICAL CHEMISTRY, 2007年04月, ［査読有り］

Sediment certified reference materials for the determination of polychlorinated biphenyls and organochlorine pesticides from the National Metrology Institute of Japan (NMIJ)　　　　　　　　　　　　　　　
M. Numata; T. Yarita; Y. Aoyagi; Y. Tsuda; M. Yamazaki; A. Takatsu; K. Ishikawa; K. Chiba; K. Okamoto, 責任著者, Springer
Anal. Bioanal. Chem., 2007年03月, ［査読有り］

Matrix certified reference materials for environmental monitoring from the National Metrology Institute of Japan (NMIJ)　　　　　　　　　　　　　　　
T. Yarita; A. Takatsu; K. Inagaki; M. Numata; K. Chiba; K. Okamoto, 筆頭著者, Springer
Accred. Qual. Assur., 2007年03月, ［査読有り］

Development of wastewater certified reference material for determination of dioxins
Yoshio Iida; Mariko Murayama; Takashi Yarita; Yoshinori Takata; Takuzo Takasuga; Shozo Asada; Yasusuke Matsumoto; Yo-Ichi Ishibashi; Hiroyuki Igaki; Tohru Matsumura; Satoshi Tsuruta; Hidekazu Ohta; Akihiro Ono; Kazutoshi Kakita; Mamoru Sakata, The Japan Society for Chemical Analysis has developed a wastewater certified reference material for the determination of dioxins (polychlorodibenzo-p-dioxins, polychlorodibenzofurans and dioxin-like polychlorobiphenyls). This reference material is the first wastewater certified reference material for the analysis of dioxins. There has been no wastewater reference material until now because wastewater is heterogeneous, consisting of water and fine suspended substances where almost all of the dioxins are absorbed; it has been considered that the reference material should be homogeneous, in principle. Then, after setting a principle that the total content of a bottle should be analyzed in one analysis, the project team obtained a success to develop a wastewater certified reference material by studying the sampling methods of wastewater to many bottles. An interlaboratory comparison test was performed by participants from 26 laboratories. Certified values with uncertainty were obtained by treating reported data statistically after rejecting outliers. The certified value of this reference material is 13.81 TEQ pg L-1, which is on the same level to as the wastewater quality of dioxins issued as the Japanese governmental standard., JAPAN SOC ANALYTICAL CHEMISTRY
BUNSEKI KAGAKU, 2007年01月, ［査読有り］

ダイオキシン類分析用排水認証標準物質の開発　　　　　　　　　　　　　　　
飯田芳男; 村山真理子; 鎗田孝; 高田芳矩; 高菅卓三; 浅田正三; 松本保輔; 石橋耀一; 松村徹; 鶴田暁; 太田秀和; 小野昭紘; 柿田和俊; 坂田衛, 日本分析化学会
分析化学, 2007年01月, ［査読有り］

Comparison of the behavior of C-13- and deuterium-labeled polycyclic aromatic hydrocarbons in analyses by isotope dilution mass spectrometry in combination with pressurized liquid extraction
Nobuyasu Itoh; Masahiko Numata; Yoshie Aoyagi; Takashi Yarita, We examined the differences found in the concentrations of polycyclic aromatic hydrocarbons (PAHs) in sediment samples when determined by isotope dilution mass spectrometry (IDMS) using C-13-labeled PAHs (C-13-PAHs) and deuterium-labeled PAHs (PAHs-d) as internal standards. The samples were analyzed by pressurized liquid extraction (PLE) in combination with gas chromatography-mass spectrometry. The observed concentrations with PAHs-d as internal standards were significantly (p < 0.05) lower (1.9-4.3%) than those determined with C-13-PAHs. The most important factor responsible for the high recovery of PAHs-d relative to C-13-PAHs and native PAHs is the higher stability of PAHs-d during the PLE process. (c) 2006 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
JOURNAL OF CHROMATOGRAPHY A, 2007年01月, ［査読有り］

Effect of residues remaining in the injection liner of a gas chromatograph on the quantification of polycyclic aromatic hydrocarbons by isotope dilution mass spectrometry using deuterium-labeled internal standards
Nobuyasu Itoh; Masahiko Numata; Yoshie Aoyagi; Takashi Yarita, We have investigated the differences in response ratios of native polycyclic aromatic hydrocarbons (native PAHs)/C-13-labeled PAHs (C-13-PAHs) and of native PAHs/deuterium-labeled PAHs (PAHs-d) in a calibration solution containing at trace concentrations (< 1 mu g mL(-1)) by gas chromatography-mass spectrometry. Only the ratios of native PAHs/PAHs-d decreased significantly (p < 0.05) accompanied with increase of residue amounts originated from immediately before injected solution. Since the analytical results using PAHs-d as internal standards were significantly lower than those using C-13-PAHs whatever solutions were injected immediately before (p < 0.05, 1.9-13.2%), C-13-PAHs gave more accurate results. (c) 2006 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
JOURNAL OF CHROMATOGRAPHY A, 2006年11月, ［査読有り］

Evaluation of supercritical fluid extraction for isotope dilution gas chromatography-mass spectrometric quantification of polychlorinated biphenyls in sediment
Takashi Yarita; Yoshie Aoyagi; Masahiko Numata; Akiko Takatsu, Supercritical fluid extraction (SFE),has been evaluated as an extraction technique for the isotope-dilution quantification of polychlorinated biphenyls (PCBs) in a sediment sample. A high-resolution mass-spectrometric system equipped with a gas chromatograph was employed for the determination of seven target PCB congeners. The effect of the operation parameters on the SFE efficiency was investigated, in which the analytical values of five target PCB congeners significantly increased with increases in the extraction temperature and pressure, and that of 4,4'-dichlorobiphenyl further increased by applying static extraction. The following conditions were found to be optimal: extraction temperature, 140 degrees C; pressure, 30 MPa; time and mode, static for 15 min then dynamic for 30 min. Under these conditions, the addition of modifiers influenced the extraction of polar compounds, but did not affect the analytical values of the PCB congeners: The optimized method was suitable for high-throughput analysis as well as for providing accurate analytical results, which were comparable to or better than the analytical results obtained by Soxhlet extraction., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, 2006年11月, ［査読有り］

Optimization of the do pant for the trace determination of polycyclic aromatic hydrocarbons by liquid chromatography/dopant-assisted atmospheric-pressure photoionization/mass spectrometry
Nobuyasu Itoh; Yoshie Aoyagi; Takashi Yarita, The composition of the dopant for the analysis of polycyclic aromatic hydrocarbons (PAHs) by liquid chromatography/dopant-assisted atmospheric-pressure photoionization/mass spectrometry under reversed-phase conditions was optimized to enhance the ionization efficiency for PAHs. The most suitable dopant was a toluene/anisole mixture (99.5:0.5, v/v) and it could improve limit of detections (LODs) to 0.79-168 ng mL(-1) (signal-to-noise (S/N) = 3) for 16 common PAHs. The LODs are 3.8-40 times lower than those obtained with toluene alone and are comparable to those obtained using gas chromatography/mass spectrometry. (c) 2006 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
JOURNAL OF CHROMATOGRAPHY A, 2006年10月, ［査読有り］

Study on gas chromatographic separation on the basis of the results of interlaboratory comparison examination and proficiency testing for determination of dioxins
Yoshio Iida; Mariko Murayama; Takashi Yarita; Shozo Asada; Yasusuke Matsumoto; Yoshinori Takata; Yo-ichi Ishibashi; Hiroyuki Igaki; Tohru Matsumura; Satoshi Tsuruta; Takuzo Takasuga; Akihiro Ono; Kazutoshi Kakita; Mamoru Sakata, In the analysis of dioxins (PCDDs, PCDFs, and DL-PCBs) whose isomers in total are more than 400 using gas chromatography-mass spectrometry, it is essential to design a suitable gas chromatographic condition to separate the peaks to be measured from other peaks. For this purpose, the literature was surveyed at first to know the separation ability of recent liquid phases for gas chromatographic columns, followed by characterization of experimental data obtained from three interlaboratory testings. A statistical calculation was applied to the results mentioned above to distinguish the separated peaks from the overlapped ones. Confident results were obtained after rejecting data of the overlapped peaks., JAPAN SOC ANALYTICAL CHEMISTRY
BUNSEKI KAGAKU, 2006年08月, ［査読有り］

ダイオキシン類定量に関する共同実験及び技能試験結果に基づくガスクロマトグラフ分離の検討　　　　　　　　　　　　　　　
飯田芳男; 村山真理子; 鎗田孝; 浅田正三; 松本保輔; 高田芳矩; 石橋耀一; 井垣浩侑; 松村徹; 鶴田暁; 高菅卓三; 小野昭紘; 柿田和俊; 坂田衛, 日本分析化学会
分析化学, 2006年08月, ［査読有り］

Analytical sensitivity of arsenobetaine on atomic spectrometric analysis and the purity of synthetic arsenobetaine
T. Narukawa; T. Kuroiwa; T. Yarita; K. Chiba, Wiley
Appl. Organometal. Chem., 2006年08月, ［査読有り］

Preparation and certification of new reference materials, combustion dust (JSAC 0511 and JSAC 0512) for determination of dioxins
Y Iida; M Murayama; T Yarita; S Asada; Y Matsumoto; Y Takata; YI Ishibashi; H Igaka; T Matsumura; T Hashiba; S Tsuruta; T Takasuga; A Ono; K Kakita; M Sayata, The Japan Society for Analytical Chemistry has developed two new certified reference materials (CRMs) for analyses of dioxins (polyclilorodibenzo-p- dioxins and polychlorodibenzofurans) and coplanar polychlorobiphenyls. A project team was organized to prepare two kinds of combustion dust and to certify the concentration of dioxins and polychlorobiphenyls. An interlaboFatory comparison test was performed by participants from 23 laboratories. In a statistical analysis, Z scores in a robust method were applied to reject outliers, followed by the usual statistical procedure. The presented CRMs are expected to be useful for the quality assurance and the quality control of dioxins analysis., JAPAN SOC ANALYTICAL CHEMISTRY
BUNSEKI KAGAKU, 2006年05月, ［査読有り］

ばいじん中ダイオキシン類分析用標準物質JSAC0511, JSAC0512の開発　　　　　　　　　　　　　　　
飯田芳男; 村山真理子; 鎗田孝; 浅田正三; 松本保輔; 高田芳矩; 石橋耀一; 井垣浩侑; 松村徹; 橋場常雄; 鶴田暁; 高菅卓三; 小野昭紘; 柿田和俊; 坂田衛, 日本分析化学会
分析化学, 2006年05月, ［査読有り］

Separation of polychlorinated biphenyls from mineral oil using alkylammonium ion-bonded silica stationary phases
M Numata; Y Aoyagi; Y Tsuda; T Yarita; A Takatsu, The potential of alkylammonium ion-bonded silica stationary phases for effective and simple pretreatment for determination of polychlorinated biphenyls (PCBs) in mineral oil samples is presented in this paper. The separation between PCBs and aliphatic hydrocarbons by normal phase chromatography was improved by using the alkylammonium ion-bonded silica stationary phases instead of alkylamine-bonded silica or other polar stationary phases. The number of alkyl residues bonded to the nitrogen atom was also an important factor of the separation., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, 2006年05月, ［査読有り］

Determination of selenium in sediment by isotope dilution inductively coupled plasma mass spectrometry with an octopole reaction cell　　　　　　　　　　　　　　　
K. Inagaki; A. Takatsu; A. Nakama; S. Eyama; T. Yarita; K. Okamoto; K. Chiba, Springer
Anal. Bioanal. Chem., 2006年04月, ［査読有り］

Development of a method for the determination of organic contaminants in biological tissue and its application to international comparisons
M Numata; T Yarita; Y Aoyagi; M Yamazaki; Y Yamamoto; A Takatsu; K Ishikawa, An analytical method for the determination of persistent organic pollutants in biological tissues by using pressurized fluid extraction (PFE), followed by isotope-dilution gas chromatography/mass spectrometry, has been established. We participated in international comparisons (CCQM-P40, 57, 67) on the determination of organic contaminants in mussel (Mytilus edulis) tissue between national metrology institutes by using an analytical method. Details of our results for the determination of the target compounds (five polychlorinated biphenyl congeners, two pesticides and five polycyclic aromatic hydrocarbons) are described in terms of a quantification procedure using an equation that has been used to describe the isotope-dilution method, and an evaluation of the uncertainties of the measurement. Some results of the international comparisons are also given, in which our results are comparable to those reported by a majority of the participants., JAPAN SOC ANALYTICAL CHEMISTRY
BUNSEKI KAGAKU, 2006年01月, ［査読有り］

生物試料中の有機汚染物質分析法の開発および関連する国際比較への参加　　　　　　　　　　　　　　　
沼田雅彦; 鎗田孝; 青柳嘉枝; 山崎美佐子; 山本葉子; 高津章子; 石川啓一郎, 日本分析化学会
分析化学, 2006年01月, ［査読有り］

Superheated water chromatography of low molecular weight polyethylene glycols with ultraviolet detection
T Yarita; Y Nakajima; K Shimada; S Kinugasa; M Shibukawa, Superheated water chromatography (SWC) with ultraviolet detection was applied to the separation of low molecular weight polyethylene glycols (PEGs). PEG oligomers could be detected sensitively when the detection wavelength was set at 190 nm. The effect of column temperature on the separation of PEG oligomers was investigated. The elution time of all PEG oligomers decreased with increase in the column temperature; linear. relationships were obtained between In k and 1/T. A temperature-programmed SWC separation enabled the baseline separation of a PEG 200 sample within 56 min., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, 2005年08月, ［査読有り］

ダイオキシン類及びポリ塩化ビフェニル同族体分析用海域底質標準物質の開発
保母敏行; 村山真理子; 浅田正三; 井垣浩侑; 鎗田孝; 石橋耀一; 鶴田暁; 松本保輔; 柿田和俊; 小野昭紘; 坂田衛, The Japan Society for Analytical Chemistry has developed two new certified reference materials (CRMs) for dioxins : coplanar PCBs and 1∿10 chlorinated PCB homologues. A project team has been organized to prepare 2 kinds of marine sediment and to certify the concentration of dioxins and polychlorobiphenyls. An interlaboratory comparison test was performed by participants from 24 laboratories. In a statistical analysis, the z scores in robust method were applied to reject outliers, followed by the usual statistical procedure. The presented CRMs are expected to be useful for the quality assurance and quality control of dioxins analysis., 日本分析化学会
分析化学, 2005年04月, ［査読有り］

Analytical method comparison for the accurate determination of PCBs in sediments　　　　　　　　　　　　　　　
M. Numata; T. Yarita; Y. Aoyagi; M. Yamazaki; A. Takatsu, Internal. Symp. Halogenated Persistent Org. Poll.
Organohalogen Compds., 2004年09月

Evaluation of a microwave-assisted extraction technique for the determination of polychlorinated biphenyls and organochlorine pesticides in sediments
M Numata; T Yarita; Y Aoyagi; A Takatsu, A microwave-assisted extraction (MAE) technique for the determination of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in marine sediment samples has been investigated. The analytes were extracted under different treatment conditions, such as temperature, time and extraction solvent. They were quantified by an isotope-dilution method, and the observed concentrations and recovery yields obtained under different conditions were compared. The results of a comparison between this MAE and other extraction techniques, such as pressurized fluid extraction, saponification, sonication, and Soxhlet extraction, are also given in this report. The techniques gave comparable results with the values obtained by other extraction techniques and the certified values in the samples. However, the observed concentration values of mono- and dichlorinated biphenyls varied depending on the extraction temperature., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, 2004年05月, ［査読有り］

International comparison on the determination of polychlorinated biphenyl congeners in sediment
T Yarita; A Nakama; K Yoshimura; A Takatsu; K Okamoto, An international comparison (CCQM-P17) on the determination of polychlorinated biphenyl (PCB) congeners in sediment by national metrology institutes was carried out. We participated in this comparison by applying pressurized fluid extraction (PFE), followed by isotope-dilution gas chromatography/mass spectrometry (ID-GC/MS). Details of our results for the determination of the four target congeners are described in terms of a quantification procedure using an equation that has been used for describing the IDMS method, a comparison of the PFE efficiency with that by Soxhlet extraction, and an evaluation of the uncertainties of the measurement. Full results of the international comparison are also given, in which our results are comparable to those reported by a majority of the participants., JAPAN SOC ANALYTICAL CHEMISTRY
BUNSEKI KAGAKU, 2004年03月, ［査読有り］

底質中のポリクロロビフェニルの測定に関する国際比較　　　　　　　　　　　　　　　
鎗田孝; 仲間純子; 吉村和子; 高津章子; 岡本研作, 筆頭著者, 日本分析化学会
分析化学, 2004年03月, ［査読有り］

Determination of polychlorinated biphenyls in sediment by isotope-dilution gas chromatography/mass spectrometry with pressurized fluid extraction
T Yarita; A Nakama; M Numata; Y Aoyagi; M Yamazaki; A Takatsu, A rapid and accurate method for the determination of polychlorinated biphenyls (PCBs) in sediments was developed using pressurized fluid extraction (PFE) and isotope-dilution gas chromatography/mass spectrometry (ID-GC/MS). Four PCB congeners used as the target compounds could be quantified using an equation that has been used for describing the IDMS method. The PFE behavior of PCBs from a sediment sample was evaluated in terms of the extraction solvent, pressure and temperature, and the PFE conditions were established so as to provide a higher extraction efficiency, as follows: extraction solvent, hexane/acetone (1 : 1, v/v); extraction pressure, 15 MPa; extraction temperature, 150 degreesC; static time, 30 min. Under these conditions, the recoveries of C-13(12)-labelled PCB congeners spiked onto the sediment sample were in the range of 79.5similar to86.8%, and no significant degradation of target PCB congeners was observed. The present method was then applied to an analysis of a certified reference material, 536 (PCBs in freshwater harbor sediment), supplied by the Community Bureau of Reference, and compared with those using Soxhlet extraction; the present method was suitable for the rapid and accurate determination of PCB congeners., JAPAN SOC ANALYTICAL CHEMISTRY
BUNSEKI KAGAKU, 2003年11月, ［査読有り］

加圧流体抽出法及び同位体希釈－ガスクロマトグラフィー／質量分析法による底質中ポリクロロビフェニルの定量　　　　　　　　　　　　　　　
鎗田孝; 仲間純子; 沼田雅彦; 青柳嘉枝; 山崎美佐子; 高津章子, 筆頭著者, 日本分析化学会
分析化学, 2003年11月, ［査読有り］

超高温水クロマトグラフィー-水素炎イオン化検出法によるアルコール類の分析
中島良司; 鎗田孝; 渋川雅美, 責任著者, GCの検出法の一つであるFIDをSWCに適用し,アルコール類の分析を行った.SWCからの溶出液はその一部をスプリットし,溶融シリカキャピラリー管を介してFID装置へ導入した.本法におけるFIDの操作条件,すなわちFIDノズル内のキャピラリー管の先端位置,及び水素とヘリウムの流量を最適化した.最適条件でのメタノール,エタノール,1-プロパノール,1-ブタノール及び1-ペンタノールの検出下限値(S/N=3)は,26～57 ngの範囲であった.また, n-アルコールの保持はカラム温度の上昇に伴い減少し,移動相圧力の増加に伴い増加することが明らかとなった.本法をワイン中のエタノールの分析に適用し,GC/MSによる測定値との比較を行った結果,両法により得られた測定値はよく一致した., 日本分析化学会
分析化学, 2003年05月, ［査読有り］

Microwave-assisted steam distillation for simple determination of polychlorinated biphenyls and organochlorine pesticides in sediments
M Numata; T Yarita; Y Aoyagi; A Takatsu, A novel sample extraction technique for polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) analysis using microwave-heating device is developed. In this study, microwave-assisted extraction (MAE) and steam distillation techniques were combined. Desorption of the anatytes from solid matrixes was accelerated with water vapor which was generated by microwave irradiation. A sample holder in a commercial microwave extraction cell kept the sample from direct contact with the organic solvent for analytes trapping during the treatment process. Therefore, relatively clean extracts were obtained with small amount of solvents. Without any cleanup steps, the obtained extract could be analyzed with gas chromatograph/mass spectrometers (GC/MS). Six PCB congeners (PCB15, 28, 70, 101, 180, 194, 209) and three OCPs (gamma-HCH, 4,4'-DDE, 4,4'-DDD) in two marine sediment samples (a sediment collected from a bay of Kyusyu Island, Japan, and a certified reference material NIST SRM1944) were analyzed by using this microwave-assisted steam distillation (MASD) technique and another extraction method (exhaustive steam distillation, MAE, and Soxhlet extraction); and comparisons of the results are shown in this report. Although recovery yields of highly chlorinated biphenyls (PCB180, 194, 209) and relatively polar OCPs (gamma-HCH, 4,4'-DDD) were low (30-60%) compared with other analytes (PCB 15, 28, 70, 101, 4,4'-DDE; recovery, 80-100%), use of isotope labeled internal standards for the MASD technique gave comparable results with the values obtained by other extraction methods and the certified values in the samples., AMER CHEMICAL SOC
ANALYTICAL CHEMISTRY, 2003年03月, ［査読有り］

Superheated water chromatography of phenols using poly(styrene-divinylbenzene) packings as a stationary phase
T Yarita; R Nakajima; M Shibukawa, A method for the superheated water chromatography of phenols was developed using a poly(styrene-divinylbenzene) (PSDVB) stationary phase. The stationary phase of superheated water chromatography must be stable against the attack of water. A durability test for PSDVB packings and octadecylsilyl (ODS)-silica gels indicated that PSDVB packings were stable in superheated water in the temperature range of 100 - 150degreesC, whereas octadecylsilyl groups of ODS-silica gels cleaved even at 100degreesC. The retention of phenols on the PSDVB stationary phase decreased with an elevation of the column temperature. The retention mechanism was characterized using a thermodynamic theory that has been used for describing retention in conventional RP-HPLC. The application of the present method to an environmental analysis was also demonstrated, in which a suitable separation with good peak shape was obtained for p-chlorophenol in river-water samples., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, 2003年02月, ［査読有り］

Determination of ethanol in alcoholic beverages by high-performance liquid chromatography-flame ionization detection using pure water as mobile phase
T Yarita; R Nakajima; S Otsuka; T Ihara; A Takatsu; M Shibukawa, A method for the determination of ethanol in alcoholic beverages by high-performance liquid chromatography-flame ionization detection (HPLC-FID) was developed. An FID system could be directly connected to an HPLC system using pure water as a mobile phase. In a durability test using triacontylsilyl (C-30)-silica gel stationary phase for 96 h, no significant change in the retention time of four alcohol compounds was observed. So the HPLC separation of alcoholic beverages was carried out on the C-30-silica gel stationary phase. On application to the analysis of six kinds of alcoholic beverages, ethanol could be determined accurately by the proposed method. (C) 2002 Elsevier Science B.V. All rights reserved., ELSEVIER SCIENCE BV
JOURNAL OF CHROMATOGRAPHY A, 2002年11月, ［査読有り］

Microwave assisted steam distillation for the determination of PCBs in sediments　　　　　　　　　　　　　　　
M. Numata; T. Yarita; Y. Aoyagi; A. Takatsu, Internal. Symp. Halogenated Persistent Org. Poll.
Organohalogen Compds., 2002年

Extraction behavior of accelerated solvent extraction of DDT metabolite from fish matrix　　　　　　　　　　　　　　　
T. Yarita, Jpn. Soc. Anal. Chem.
Anal. Sci., 2001年12月, ［査読有り］

Carbon-13 NMR chemical shifts of dimeric model compounds of poly(propylene Oxide): a proof of existence of the (C-H)…O attraction
Y. Sasanuma; T. Iwata; Y. Kato; H. Kato; T. Yarita; S. Kinugasa; R. V. Law, Conformational energies of poly(propylene oxide) (PPO) have been determined from C-13 NMR chemical shifts of its six dimeric model compounds. The model compounds were prepared and fractionated by supercritical fluid chromatography into three components: CH3OCH2CH(CH3)OCH2CH(CH3)OCH3 (head-to-tail); CH3OCH2CH(CH3)OCH(CH3)CH2OCH3 (head-to-head); CH3OCH(CH3) CH2OCH2CH(CH3)OCH3 (tail-to-tail). Carbon-13 NMR measurements using H-1 broad-band decoupling and DEPT techniques were carried out for the benzene solutions at 25 degreesC, and all observed NMR peaks were assigned to the methine, methylene, pendant methyl, and terminal methoxy carbons. By the simulation based on the rotational isomeric state (RIS) scheme and gamma- and delta -substituent effects for the C-13 NMR chemical shifts, the gamma- and delta -effect parameters and the conformational energies were optimized; the root-mean-square error between the calculated and observed chemical shifts was minimized to 0.12 ppm. Values of the gamma -anti effect (-2.6 ppm) of oxygen, the gamma -gauche effects of carbon (-4.9 ppm) and oxygen (-7.9 ppm), and the delta -effect (2.1 ppm) of oxygen for the g(+)g(-) conformations were obtained to fall within the allowable ranges, as shown in the parentheses. The conformational energies evaluated here are comparable to those determined for isotactic PPO in our previous studies. These results confirm our interpretation of the gauche oxygen effect: The gauche stability of the C-C bond in the main chain of PPO is due to the intramolecular (C-H). . .O hydrogen bonding., Am. Chem. Soc.
J. Phy. Chem. A, 2001年04月, ［査読有り］

Accelerated solvent extraction of organochlorine pollutants from fish matrix　　　　　　　　　　　　　　　
T. Yarita; A. Nomura, 筆頭著者
Proceeding of the 22nd International Symposium on Capillary Chromatography, 1999年11月

Endcapping of octadecylsilyl-silica gels using supercritical fluid as reaction medium
T Yarita; T Ihara; Y Horimoto; A Nomura, A method for endcapping of octadecylsilyl (ODS)-silica gels was developed using supercritical carbon dioxide as a silylation medium. The effects of temperature and pressure of carbon dioxide on the deactivation of the gels were investigated under the silylation conditions at 100 - 220 degrees C and 11.8 - 24.5 MPa. High-performance liquid chromatographic evaluation using caffeine and phenol as test compounds indicated that the most inert gels were obtained from the endcapping under 180 degrees C and 24.5 MPa. Endcapped ODS-silica gels, which were commercially available, could be further deactivated under these conditions. The inertness of the gels was also evaluated by supercritical fluid chromatography (SFC) using pyridine and phenol as test compounds. The effectiveness of the proposed method war clearly observed in the SFC evaluation., JAPAN SOC ANALYTICAL CHEMISTRY
ANALYTICAL SCIENCES, 1999年04月, ［査読有り］

Development of separation and quantification methods for organic compounds using supercritical fluids
T Yarita, Separation and quantification methods using supercritical fluids have been developed in terms of separation, detection and hyphenation techniques as well as an application to real sample analyses. For sensitive and selective detection in supercritical fluid chromatography (SFC), an electron-capture detector was used as a detector; small quantities of organochlorine pollutants could be determined. A novel deactivation method of silica-based column packings using supercritical fluid carbon dioxide as a reaction medium was also reported. The effectiveness of this method was higher than that of the classical method using organic solvents. On the other hand, the use of a modifier in supercritical fluid extraction (SFE) of small quantities of triazine herbicides in soil was investigated; the addition of methanol as a modifier increased the recoveries of the herbicides. Regarding the hyphenated system, on-line SFC/GC and SFE/SFC systems were investigated; a type analysis of essential oils and residue analysis of thiolcarbamate herbicides could be rapidly performed using these systems. The results obtained in this study indicate that the proposed methods are useful for the sensitive and rapid determination of organic compounds., JAPAN SOC ANALYTICAL CHEM
BUNSEKI KAGAKU, 1998年08月, ［査読有り］

Liquid chromatography mass spectrometric analysis of phenylurea herbicides and their degradation products using an atmospheric pressure ionization interface
T Yarita; K Sugino; T Ihara; A Nomura, A method was developed for the determination of two phenylurea herbicides and their degradation products using liquid chromatography-atmospheric pressure chemical ionization (APCI)-mass spectrometry without any additives in the mobile phase, The APCI detection sensitivity of these compounds was maximized when the vaporizer temperature was set at 250 degrees C and a positive-ion detection mode was chosen. Under these conditions, the detection limits (S/N = 3) of these compounds in total-ion and selected-ion monitoring mere 2.5-3.0 and 0.12-0.26 ng, respectively. In a biodegradability test on diuron, small quantities of degradation products could be determined by the proposed method., ROYAL SOC CHEMISTRY
ANALYTICAL COMMUNICATIONS, 1998年03月, ［査読有り］

On-line coupled supercritical fluid extraction and chromatography for the determination of thiolcarbamate herbicides in soil matrix
T Yarita; A Nomura; Y Horimoto; S Gonda, Supercritical fluid extraction (SFE) was on-line coupled with supercritical fluid chromatography (SFC) for the determination of thiolcarbamate herbicides in soil matrix. Inert ODS-silica gel packings were used as a trap column for an interface between SFE and SFC and as an analytical column for the satisfactory separation of extracts. Thiolcarbamate herbicides could be extracted satisfactorily from the soil matrix, which had different characteristics. The results indicated that the proposed system was useful for the rapid determination of thiolcarbamate herbicides in soil matrices., ELSEVIER SCIENCE BV
JOURNAL OF CHROMATOGRAPHY A, 1996年10月, ［査読有り］

Supercritical fluid extraction of triazine herbicides from soil matrix
T. Yarita; Y. Horimoto; A. Nomura; S. Gonda, 筆頭著者, A method of supercritical fluid extraction (SFE) of triazine herbicides from soil has been developed. The recoveries of triazine herbicides increased with increase in both extraction pressure and temperature when supercritical carbon dioxide was used as the extraction medium alone. Because the recovery by SFE was influenced by the concentration of triazine herbicides in the soil matrix, the addition of methanol to carbon dioxide as a polar modifier was required for the satisfactory extraction of trace levels of the content of the herbicides. The moisture content of the soil also affected the recoveries by SFE. SFE was applied to the analysis of real samples. The results by SFE were almost the same as those from soxhlet extraction., Vieweg+Teubner Verlag
Chromatographia, 1996年10月, ［査読有り］

In situ silylation of silica-based packings using supercritical fluid as reaction medium
T Yarita; A Nomura; Y Horimoto, A method for in situ silylation was developed using supercritical carbon dioxide as a reaction medium and was applied to an endcapping of ODS-silica gels as well as a trimethylsilylation of silica gels. The results of pyridine/phenol test and surface coverage of silica-based packings were improved by the proposed method. It was indicated that supercritical fluid is more effective than organic solvents as the silylation medium., ELSEVIER SCIENCE BV
JOURNAL OF CHROMATOGRAPHY A, 1996年02月, ［査読有り］

SUPERCRITICAL-FLUID CHROMATOGRAPHY OF FREE RESIN ACIDS ON AN ODS SILICA-GEL COLUMN
A YAMADA; Y EZAKI; K MATSUO; T YARITA; A NOMURA, The supercritical fluid chromatographic behaviour of resin acids on an inert ODS-silica gel column using supercritical carbon dioxide as the mobile phase was studied. The separation of resin acids could be achieved considerably better by using methanol as a modifier. According to these results, the isomers of abietane-type acids could be separated by SFC without derivatization, particularly esterification., ELSEVIER SCIENCE BV
JOURNAL OF CHROMATOGRAPHY A, 1995年08月, ［査読有り］

Supercritical fluid chromatographic determination of tocopherols on an ODS- silica gel column　　　　　　　　　　　　　　　
T. Yarita; A. Nomura; K. Abe; Y. Takeshita, 筆頭著者, Elsevier
J. Chromatogr. A, 1995年08月, ［査読有り］

DETERMINATION OF FREE FATTY-ACIDS BY SUPERCRITICAL-FLUID CHROMATOGRAPHY ON AN ODS SILICA-GEL COLUMN
A NOMURA; J YAMADA; T YARITA; Y SUDO; S KUDO; Y NISHIZAWA, Free fatty acids (FFAs) were determined by supercritical-fluid chromatography (SFC) on an inert ODS silica-gel column using carbon dioxide as a mobile phase without a modifier. The standard samples of FFAs with carbon numbers of 6 to 26 (even numbers) were completely separated using the pressure-programming mode. The retention behavior of FFAs was investigated in terms of the density of the mobile phase, and the FFAs were separated according to a reversed-phase mode in liquid-chromatographic terms. The composition of fatty acids of coconut oil was determined by the SFC, and was compared with gas chromatography. A good agreement was obtained. The chromatographic separation of FFAs obtained from fish oil as well as the enzymatic hydrolysis products of the fish oil were also conducted., JAPAN SOC ANALYTICAL CHEM
ANALYTICAL SCIENCES, 1995年06月, ［査読有り］

Supercritical-fluid chromatograms of fuel oils on ods-silica gel column using fluorescence, UV-absorption, and flame-ionization detectors
Akira Nomura; Joseph Yamada; Takashi Yarita; Tsuneaki Maeda, Chromatographic patterns of fuel oils such as kerosene, diesel oil, and sand oil were compared by supercritical-fluid chromatography (SFC) on an ODS-silica gel column using fluorescence detector (FD), UV-absorption detector (UV), and flame-ionization detector (FID). The quartz FD cell in a square-pillared shape with square cross section was made and used to selectively detect polyaromatic hydrocarbons in fuel oils. The chromatographic profiles simultaneously obtained by FD, UV, and FID differed according to the properties of the components in the fuel oils. © 1995., PRA Press
The Journal of Supercritical Fluids, 1995年, ［査読有り］

DETERMINATION OF CHLORINATED PESTICIDES BY PACKED-COLUMN SUPERCRITICAL-FLUID CHROMATOGRAPHY ELECTRON-CAPTURE DETECTOR
T YARITA; A NOMURA; Y HORIMOTO; J YAMADA, An electron-capture detector (ECD) was used in packed column supercritical fluid chromatography (SFC) for the selective determination of chlorinated pesticides. The separation of chlorinated pesticides was conducted on an ODS-silica gel column using carbon dioxide as a mobile phase without a modifier. The detection temperature of ECD was set to 325-degrees-C according to the peak sensitivities. The SFC/ECD system was applied to the determination of gamma-BHC and p, p'-DDD in carrots extracted by supercritical fluid extraction. The recoveries of gamma-BHC and p, p'-DDD obtained by the SFC/ECD were 93.9 and 93.2%, respectively. (C) 1994 Academic Press, Inc., ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS
MICROCHEMICAL JOURNAL, 1994年04月, ［査読有り］

TYPE ANALYSIS OF CITRUS ESSENTIAL OILS BY MULTIDIMENSIONAL SUPERCRITICAL-FLUID CHROMATOGRAPHY GAS-CHROMATOGRAPHY
T YARITA; A NOMURA; Y HORIMOTO, A multidimensional supercritical fluid chromatography (SFC)/gas chromatography (GC) system was developed for the characterization of citrus essential oils. For on-line coupling of SFC with GC, the carbon dioxide mobile phase used in the SFC was split after a UV detector and then introduced into a GC injector. The elution order in the SFC on a silica-gel column was based on the polarities of the solutes. First, citrus essential oils were separated into three fractions (hydrocarbons, aldehydes and esters, and alcohols) by SFC utilizing stepwise pressure programming. Then, each fraction was introduced into the GC and determined using a flame ionization detector for the quantification of three fractions as well as their components in the oils. The SFC/GC system was applied to the characterization of citrus essential oils. All of the citrus essential oils used in this study mainly consisted of hydrocarbons., JAPAN SOC ANALYTICAL CHEM
ANALYTICAL SCIENCES, 1994年02月, ［査読有り］

SUPERCRITICAL-FLUID CHROMATOGRAPHIC DETERMINATION OF CHOLESTEROL AND CHOLESTERYL ESTERS IN SERUM ON ODS-SILICA GEL COLUMN
A NOMURA; J YAMADA; A TAKATSU; Y HORIMOTO; T YARITA, Cholesterol and cholesteryl esters in human serum were determined by supercritical fluid chromatography on an inert ODS-silica gel column using supercritical carbon dioxide as a mobile phase without a modifier. Chromatograms were obtained by monitoring the eluent simultaneously with an FID and UV detector at the wavelength of 190 nm. The retention behavior of cholesterol and cholesteryl esters was investigated in terms of the density of CO2 mobile phase. The separation mode was found to be reversed phase, as in liquid chromatography. The amounts of cholesterol and cholesteryl esters extracted from human serum reference material (NIST SRM 909) were determined individually using cholesteryl laurate as an internal standard to give good agreement of total cholesterol with the value certified by NIST., AMER CHEMICAL SOC
ANALYTICAL CHEMISTRY, 1993年08月, ［査読有り］

SUPERCRITICAL FLUID CHROMATOGRAPHIC DETERMINATION OF POLYCHLORINATED-BIPHENYLS ON AN OCTADECYLSILYL-SILICA GEL COLUMN USING AN ELECTRON-CAPTURE DETECTOR
T YARITA; Y HORIMOTO; J YAMADA; A NOMURA, Packed-column supercritical fluid chromatography (SFC) was connected to an electron-capture detector (ECD) in order to determine polychlorinated biphenyls (PCBs) in the environment. The separation of PCBs was conducted on octadecylsilyl (ODS)-silica gel columns using carbon dioxide as a mobile phase without a modifier. The detection temperature of ECD was set up to 325-degrees-C according to the sensitivity to the PCBs. The capacity factor of the PCBs was affected by the density of the mobile phase and the pore structure of ODS-silica gel. The SFC-ECD system was applied to the determination of PCBs in sediment samples using a pressure-programming mode. The base-line drift of the chromatogram was accompanied by an increase in the pressure of carbon dioxide, which could be adjusted by an integrator. The packed-column SFC detected by ECD was found to be useful for determining PCBs in the environment., JAPAN SOC ANALYTICAL CHEM
ANALYTICAL SCIENCES, 1992年12月, ［査読有り］

モリブデンとリン蒸気との反応　　　　　　　　　　　　　　　
藤代光雄; 富澤俊昭; 鎗田孝; 天野聡博; 佐々木義典, 責任著者, 電気化学協会
電気化学および工業物理化学, 1990年05月, ［査読有り］

国際基準に対応した認証標準物質の開発と技能試験の実施
大竹貴光; 鎗田孝
日本農薬学会誌, 2021年08月, ［査読有り］, ［招待有り］
責任著者

土壌・底質認証標準物質
鎗田孝
ぶんせき, 2018年10月, ［査読有り］, ［招待有り］
筆頭著者

有害物質分析のための環境・食品標準物質
鎗田孝; 成川知弘
ぶんせき, 2014年11月, ［査読有り］, ［招待有り］
筆頭著者

環境分析用標準物質
鎗田孝
ぶんせき, 2010年09月, ［査読有り］, ［招待有り］
筆頭著者

同位体希釈-誘導結合プラズマ質量分析法による底質中微量元素の全量及び化学形態別分
稲垣和三; 高津章子; 鎗田孝; 千葉光一; 岡本研作
分析化学, 2009年04月, ［査読有り］, ［招待有り］

ポリクロロビフェニル(PCB)分析用鉱物油標準物質の開発
沼田雅彦; 青柳嘉枝; 松尾真由美; 石川啓一郎; 羽成修康; 大塚聡子; 津田葉子; 鎗田孝; 岡本研作
環境と測定技術, 2008年08月, ［招待有り］

Development of Environmental Analysis Methods Using Supercritical Fluid Extraction and Supercritical Fluid Chromatography
T. Yarita
Chromatography, 2008年03月, ［査読有り］, ［招待有り］
筆頭著者

環境分析用標準物質の開発動向と産総研計量標準総合センターの取り組み
鎗田孝
産業と環境, 2005年08月, ［招待有り］
筆頭著者

底質中のPCBの精密分離・定量法
鎗田孝; 沼田雅彦
環境と測定技術, 2004年05月, ［招待有り］
筆頭著者

"超"高速液体クロマトグラフィー－超高圧・高温下での分離
鎗田孝
化学と工業, 2003年12月, ［査読有り］, ［招待有り］
筆頭著者

同位体希釈質量分析法による塩素系農薬の定量に関する国際比較
井原俊英; 吉村和子; 大手洋子; 野村明; 大塚聡子; 鎗田孝; 鮑新努
The Chemical Times, 2002年07月, ［招待有り］

環境分析における試料抽出法の比較
鎗田孝
化学と工業, 1998年09月, ［査読有り］, ［招待有り］
筆頭著者

超臨界流体を利用した有機化合物の分離定量技術の高性能化に関する研究
鎗田孝
分析化学, 1998年08月, ［査読有り］

Application of supercritical fluid extraction and chromatography to the environmental analysis
T. Yarita; Y. Horimoto; A. Nomura
物質工学工業技術研究所報告, 1997年12月, ［査読有り］
筆頭著者