116 Specific biomarkers for the exposure to organophosphate and carbamate pesticides

Abstract

Introduction Organophosphate pesticides (OPP) and carbamates are still counted among the most prominent agents used for crops protection. Up to date the determination of dialkyl phosphates and their thio derivatives in urine is established for the OPP biomonitoring. However, this approach does not provide information on the exposure to specific OPP agents. A lot of OPP as well as some carbamates also provide specific urinary biomarkers indeed. For a specific biomonitoring approach we developed an analytical procedure, which enables the assessment of a wide spectrum of phenolic metabolites of OPP and carbamates in human urine. Methods After enzymatic cleavage of possible glucuronide and sulfate conjugates, the analytes were extracted by solid phase cartridges and derivatized with N-methyl-N-(trimethylsilyl)-trifluoroacetamide. The prepared samples were determined by GC-MS/MS using electron impact ionisation and multiple reaction monitoring mode. The validated method was applied to samples derived from occupational and environmental exposure. Results The procedure enables the simultaneous quantification of 9 biomarkers for OPP exposure (4-tert-butyl-2-chlorophenol, 3-chloro-7-hydroxy-4-methylcoumarin, 2-(diethylamino)−6-methylpyrimidin-4-ol, 2-isopropoxy-6-methylpyrimidin-4-ol, 3-methyl-4-(methylthio)phenol, 3-methyl-4-nitrophenol, 4-(methylthio)phenol, 4-nitrophenol, 3,5,6-trichloro-2-pyridinol) and 7 biomarkers for carbamate exposure (2-amino-5,6-dimethylpyrimidin-4-ol, 2-(dimethylamino)−5,6-dimethyl-pyrimidin-4-ol, 2,2-dimethylbenzo[1,3]dioxol-4-ol, 2,2-dimethyl-2,3-dihydrobenzofuran-7-ol, 3,5-dimethyl-4-(methylthio)phenol, 2-isopropoxyphenol, 1-naphthol).The method showed detection limits between 0.1 and 0.3 µg/L. Variation coefficients ranged from 2% to 10% for precision in series and 2% to 14% for inter-day precision. Furthermore, recovery rates between 87% and 120% were determined. Discussion The method showed high reliability and robustness. It enables the simultaneous and specific monitoring of a wide spectrum of pesticides and biocides whose structures contain aryl moieties. The multicomponent procedure can be used for biomonitoring of agriculture workers, bystanders and general populations.