title: Simultaneous determination of urinary dialkylphosphate metabolites of organophosphorus pesticides using gas chromatography-mass spectrometry.
abstract: In this study, we developed a safe and sensitive method for the simultaneous determination of urinary dialkylphosphates (DAPs), metabolites of organophosphorus insecticides (OPs), including dimethylphosphate (DMP), diethylphosphate (DEP), dimethylthiophosphate (DMTP), and diethylthiophosphate (DETP), using a pentafluorobenzylbromide (PFBBr) derivatization and gas chromatography-mass spectrometry (GC-MS). Several parameters were investigated: pH on evaporation, reaction temperature and time for the derivatization, the use of an antioxidant for preventing oxidation, and a clean-up step. The pH was set at 6, adjusted with K2CO3, and the reaction temperature and time of derivatization were 80 degrees C and 30 min, respectively. Sodium disulfite was chosen as an antioxidant. The clean-up step was performed with a Florisil/PSE mini-column to remove the unreacted PFBBr and sample matrix. This established procedure markedly shortened the sample preparation time to only about 3 h, and completely inhibited the unwanted oxidization of dialkylthiophosphates. The limits of determination (LOD) were approximately 0.3 microg/L for DMP, and 0.1 microg/L for DEP, DMTP, and DETP in 5 mL of human urine. Within-series and between-day imprecision for the present method using pooled urine spiked with DAPs was less than 20.6% in the calibration range of 1-300 microg/L, and the mean recovery was 56.7-60.5% for DMP, 78.5-82.7% for DEP, 88.3-103.9% for DMTP, and 84.2-92.4% for DETP. This method detected geometric mean values of the urinary DAPs in Japanese with and without occupational exposure to OPs, 16.6 or 27.4 for DMP, 1.0 or 0.7 for DEP, 1.3 or 2.3 for DMTP, and 1.0 or 1.1 microg/L for DETP, respectively. The present method, which does not require special equipment except for GC-MS, is quick, safe, and sensitive enough to be adopted in routine biological monitoring of non-occupational as well as occupational exposure to OPs.
authors.affiliation: Department of Clinical Laboratory, Nagoya University Hospital, Nagoya 466-8560, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Ueyama
authors.forename: Isao
authors.initials: I
authors.lastname: Saito
authors.forename: Michihiro
authors.initials: M
authors.lastname: Kamijima
authors.forename: Tamie
authors.initials: T
authors.lastname: Nakajima
authors.forename: Masahiro
authors.initials: M
authors.lastname: Gotoh
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Eiji
authors.initials: E
authors.lastname: Shibata
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kondo
authors.forename: Kenji
authors.initials: K
authors.lastname: Takagi
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Junki
authors.initials: J
authors.lastname: Takamatsu
authors.forename: Takaaki
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Kenzo
authors.initials: K
authors.lastname: Takagi
mesh_terms: D016022:Case-Control Studies; D004784:Environmental Monitoring; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016273:Occupational Exposure; D009943:Organophosphorus Compounds / Q000652:urine*; D010575:Pesticides / Q000652:urine*; D010710:Phosphates / Q000652:urine*; D012680:Sensitivity and Specificity
chemical_list: D009943:Organophosphorus Compounds; D010575:Pesticides; D010710:Phosphates