Human exposure to organophosphorus pesticides. Modified procedure for the gas-liquid chromatographic analysis of alkyl phosphate metabolites in urine

Simultaneous determination of six dialkylphosphates in urine by liquid chromatography tandem mass spectrometry

“…Similar LLE procedures were previously reported [8,[13][14][15]16,18]. Additionally, 4 g of sodium chloride were added to urine in order to increase water density (which improves the separation between the two phases), and to improve the extraction of DAP from the aqueous phase (salt effect).…”

“…Therefore, another approach to the monitoring of organophosphates is based on the determination of these DAP in urine . Numerous methods have been proposed in this field [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Most of them are gas chromatography methods requiring derivatization prior to the analysis.…”

“…Some authors [9,10,12] have proposed to perform two derivatization steps: one at ambient temperature and one at 90 • C. Intermediate temperatures (40 and 50 • C) have also been proposed to derivatize simultaneously the DAP [7,8]. Diazoalkanes (such as diazomethane and diazopentane) were used in a few methods as derivatization reagents [13][14][15]18]. However, they are explosive and carcinogenic, they are not specific and gives mixed products with alkylating agents [9].…”

Strategies for assessing children's organophosphorus pesticide exposures in agricultural communities

“…The lack of specific metabolites for OP pesticides has made the use of the more generic dialkyl phosphate analysis attractive. The dialkyl phosphate method was first developed for occupational exposure assessments (Shafik et al, 1973 ) and allowed resolution of dimethyl and diethyl compounds. Six metabolic products are normally measured by gas chromatography following derivatization: dimethyl phosphate (DMP ), dimethylthio phosphate ( DMTP ) , dimethyldithio phosphate ( DMDTP ), diethyl phosphate ( DEP ), diethylthio phosphate ( DETP ), and diethyldithio phosphate ( DEDTP ) .…”

Identification of metabolites of malathion in plant, water and soil by GC-MS

“…It is thus evident that a major amount of it used in agroforestry or for medical purposes remains exposed to the environment. Bio-monitoring exposures to malathion has been accomplished by the determination of dimethyl thiophosphate (DMTP), dimethyldithiophosphate (DMDTP) (Shafik and Enos, 1969;Shafik et al, 1971Shafik et al, , 1973 or the carboxylesterase metabolites, malathion ␣-monoacid (␣-MMA) and malathion diacid (MDA) (Bradway and Shafik, 1977). Muan and Share (1987) have described an anion exchange, solid phase extraction procedure for malathion metabolites.…”