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Ueyama J.,Nagoya University | Saito I.,Food Safety and Quality Research Center | Kamijima M.,Nagoya City University
Journal of Pesticide Science | Year: 2010

The current risk assessment of human exposure to low-level pyrethroids (PYRs) is generally based on the estimation of residue intake from diets. Limited data are available on individual exposure levels in human studies, which is partly attributable to the difficulty in biological monitoring of PYR exposure. This obstacle has been overcome in recent years due to the evolution of analytical chemistry. Separation and sensitive identification and quantitation of urinary PYR metabolites are today reliably made with liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. This article gives an overview of the biological monitoring of urinary PYR metabolites, reviews PYR metabolite levels in general populations, and discusses future research perspectives in the field of environmental health. © Pesticide Science Society of Japan. Source


Ueyama J.,Nagoya University | Saito I.,Food Safety and Quality Research Center | Takaishi A.,Okazaki City Public Health Center | Nomura H.,Nagoya University | And 9 more authors.
Environmental Health and Preventive Medicine | Year: 2014

Objectives: Biological monitoring of organophosphorus insecticide (OP) metabolites, specifically dialkylphosphates (DAP) in urine, plays a key role in low-level exposure assessment of OP in individuals. The aims of this study are to develop a simple and sensitive method for determining four urinary DAPs using high-performance liquid chromatography with tandem mass spectrometry (LC–MS/MS), and to assess the concentration range of urinary DAP in Japanese children.Methods: Deuterium-labeled DAPs were used as internal standards. Urinary dimethylphosphate (DMP) and diethylphosphate (DEP), which passed through the solid-phase extraction (SPE) column, and dimethylthiophosphate (DMTP) and diethylthiophosphate (DETP), which were extracted from a SPE column using 2.5 % NH3 water including 50 % acetonitrile, were prepared for separation analysis. The samples were then injected into LC–MS/MS. The optimized method was applied to spot urine samples from 3-year-old children (109 males and 116 females) living in Aichi Prefecture in Japan.Conclusions: The present high-throughput method is simple and reliable, and can thereby further contribute to development of an exposure assessment of OP. The present study is the first to reveal the DAP concentrations in young Japanese children.Results: Results from the validation study demonstrated good within- and between-run precisions (<10.7 %) with low detection limits (0.4 for DMP and DMTP, 0.2 for DEP and 0.1 μg/L for DETP). The geometric mean values and detection rates of the urinary DAPs in Japanese children were 14.4 μg/L and 100 % for DMP, 5.3 μg/L and 98 % for DMTP, 5.5 μg/L and 99 % for DEP, and 0.6 μg/L and 80 % for DETP, respectively. © 2014, The Japanese Society for Hygiene. Source


Ueyama J.,Nagoya University | Kamijima M.,Nagoya City University | Kondo T.,Nagoya University | Takagi K.,Nagoya University | And 6 more authors.
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2010

Among urinary organophosphorus pesticide (OP) metabolites, dialkyl phosphates (DAPs) have been most often measured as a sensitive biomarker in non-occupational and occupational OP exposure risk assessment. In our conventional method, we have employed a procedure including simple liquid-liquid extraction (diethyl ether/acetonitrile), derivatization (pentafluorobenzylbromide, PFBBr) and clean-up (multi-layer column) for gas chromatography-mass spectrometry (GC-MS) analysis starting from 5-mL urine samples. In this study, we introduce a revised analytical method for urinary DAPs; its main modification was aimed at improving the pre-derivatization dehydration procedure. The limits of detection were approximately 0.15μg/L for dimethylphosphate (DMP), 0.07μg/L for diethylphosphate (DEP), and 0.05μg/L for both dimethylthiophosphate (DMTP) and diethylthiophosphate (DETP) in 2.5-mL human urine samples. Within-run precision (percent of relative standard deviation, %RSD) at the DAP levels varying in the range of 0.5-50μg/L was 6.0-19.1% for DMP, 3.6-18.3% for DEP, 8.0-25.6% for DMTP and 9.6-27.8% for DETP. Between-run precision at 5μg/L was below 15.7% for all DAPs. The revised method proved to be feasible to routine biological monitoring not only for occupational OP exposure but also for environmental background levels in the general population. Compared to our previous method, the revised method underscores the importance of adding pre-derivatization anhydration for higher sensitivity and precision. © 2010 Elsevier B.V. Source


Nomura H.,Nagoya University | Ueyama J.,Nagoya University | Kondo T.,Nagoya University | Saito I.,Food Safety and Quality Research Center | And 4 more authors.
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2013

A rapid and sensitive analytical method using gas chromatography-mass spectrometry (GC-MS) was developed for the measurement of neonicotinoid (NEO) metabolites 6-chloronicotinic acid (6CN), 2-chloro-1,3-thiazole-5-carboxylic acid (2CTCA) and 3-furoic acid (3FA) from human urine. After acid hydrolysis, the metabolites were extracted using solid phase extraction (SPE) column (Bond Elute Plexa PCX) and eluted with methanol. N,O-bis (trimethylsilyl) trifluoroacetamide with 1% trimethylchlorosilane (BSTFA-TMCS, 99:1) was used for the derivatization of metabolites and analyzed by GC-MS with the electron ionization mode. The elution solvent, derivatization reagent and its conditions were mainly optimized for improved detection and quantitation of the metabolites based on signal-to-noise ratio, recoveries and reproducibility. Our present method offered a sufficiently low limit of detection (0.1. μg/L for each metabolite) with satisfactory within-run and between-day accuracy and precision (variability less than 12.3%, R.S.D). This method is simple, sensitive and precise, and has been successfully applied to quantify low concentrations of urinary 6CN, 2CTCA and 3FA for the occupational NEO exposures survey. © 2013 Elsevier B.V. Source


Ueyama J.,Nagoya University | Harada K.H.,Kyoto University | Koizumi A.,Kyoto University | Sugiura Y.,Nagoya University | And 3 more authors.
Environmental Science and Technology | Year: 2015

Over the last two decades, usage of neonicotinoid (NEO) insecticides has increased due to their high selectivity for insects versus mammals and their effectiveness for extermination of insects resistant to conventional pesticides such as pyrethroids and organophosphates (OPs). However, historical change of the NEO exposure level in humans is poorly understood. The aim of this study is to reveal changes in the levels of NEO and OP exposure in the human body over the last two decades using biomonitoring technique. We quantified urinary concentrations of 7 NEOs (acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram, thiacloprid, and thiamethoxam) and 4 metabolites of OPs (dimethylphosphate, dimethylthiophosphate, diethylphosphate, and diethylthiophosphate) in 95 adult females aged 45-75 in 1994, 2000, 2003, 2009, and 2011 (n = 17-20 different individuals in each year). The results show that the detection rates of urinary NEOs in Japanese women increased significantly between 1994 and 2011, suggesting that intakes of NEOs into the human body rose during that period. In contrast, exposure to OPs having O,O-dimethyl moieties decreased steadily according to a finding that geometric means of urinary dimethylphosphate concentrations kept diminishing considerably. These changes may reflect the amounts of NEOs and OPs used as insecticides in Japan. © 2015 American Chemical Society. Source

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