Method for the determination of dialkyl phosphate metabolites in urine for studies of human exposure to malathion

Fenske, Richard A.; Leffingwell, John T.

doi:10.1021/jf00088a039

Cited by 38 publications

(21 citation statements)

References 10 publications

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“…Because the alkylation of DAP metabolites is a thermosensitive reaction and the sulfur-containing DAPs degrade at high temperatures (Fenske and Leffingwell, 1989;Moate et al, 1999;Oglobline et al, 2001 a, b), optimization of the reaction temperature and time is critical. Typically, the sulfur-containing molecules (DMTP, DMDTP, DETP, and DEDTP) react at room temperature while DMP and DEP often require high temperatures to react.…”

Section: Resultsmentioning

confidence: 99%

“…Since the 1970s, urinary dialkylphosphate (DAP) metabolites of OP pesticides have been quantified in human urine as a dosimeter for exposure and bodily adsorption of OP pesticides (Bradway and Shafik, 1977;Reid and Watts, 1981;Bardarov and Mitewa, 1989;Fenske and Leffingwell, 1989;Weisskopf and Seiber, 1989;Drevenkar et al, 1991;Aprea et al, 1994Aprea et al, , 1996aAprea et al, , b, 1999Aprea et al, , 2000Davies and Peterson, 1997;Loewenherz et al, 1997;Moate et al, 1999;Simcox et al, 1999. Fenske et al, 2000Hardt and Angerer, 2000;Heudorf and Angerer, 2001;Lu et al, 2001;Oglobline et al, 2001a, b;Bravo et al, 2002;CDC, 2002;Cocker et al, 2002;Garfitt et al, 2002a, b).…”

Section: Introductionmentioning

confidence: 99%

“…Typical isolation or extraction techniques reported in the literature include liquid-liquid extraction using polar solvents (Hardt and Angerer, 2000), solid-phase extraction (SPE) (Lores and Bradway, 1976;Weisskopf and Seiber, 1989;Driskell et al, 1999), azeotropic distillation using acetonitrile:water azeotropes (7:1) (Reid and Watts, 1981;Fenske and Leffingwell, 1989;Moate et al, 1999;Bravo et al, 2002), and lyophilization (Davies and Peterson, 1997;Oglobline et al, 2001 a, b). Because the DAP metabolites are inherently polar with low pK a 's, the liquid-liquid extraction of these metabolites into an organic phase is difficult, resulting in poor recoveries.…”

Section: Introductionmentioning

confidence: 99%

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Measurement of dialkyl phosphate metabolites of organophosphorus pesticides in human urine using lyophilization with gas chromatography-tandem mass spectrometry and isotope dilution quantification

Bravo

Caltabiano

Weerasekera

et al. 2004

J Expo Sci Environ Epidemiol

159

153

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Urinary dialkylphosphate (DAP) metabolites have been used to estimate human exposure to organophosphorus pesticides. We developed a method for quantifying the six DAP urinary metabolites of at least 28 organophosphorus pesticides using lyophilization and chemical derivatization followed by analysis using isotope-dilution gas chromatography-tandem mass spectrometry (GC-MS/MS). Urine samples were spiked with stable isotope analogues of the DAPs and the water was removed from the samples using a lyophilizer. The dried residue was dissolved in acetonitrile and diethyl ether, and the DAPs were chemically derivatized to their respective chloropropyl phosphate esters. The chloropropyl phosphate esters were concentrated, and analyzed using GC-MS/MS. The limits of detection of the method were in the low mg/l (parts per billion) to mid pg/ml range (parts per trillion) with coefficients of variation of 7-14%. The use of stable isotope analogues as internal standards for each of these metabolites allows for sample-specific adjustment for recovery and thus permits a high degree of accuracy and precision. Use of this method with approximately 1100 urine samples collected from pregnant women and children indicate that the low limits of detection allow this method to be used in general population studies.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Measurement of dialkyl phosphate metabolites of organophosphorus pesticides in human urine using lyophilization with gas chromatography-tandem mass spectrometry and isotope dilution quantification

Bravo

Caltabiano

Weerasekera

et al. 2004

J Expo Sci Environ Epidemiol

159

153

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“…Both MDA and 2,4 -D have been analyzed using GC with electron -capture detection (GC -ECD ), NPD or GC -MS (Bradway and Shafik, 1977;Fenske and Leffingwell, 1989;Draper et al, 1991;Hill et al, 1995a;Aprea et al, 1997a ). These methods require a derivatization step that can be time -consuming and often requires additional cleanup steps to improve sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Quantification of selected pesticide metabolites in human urine using isotope dilution high-performance liquid chromatography/tandem mass spectrometry

Baker

Barr

Driskell

et al. 2000

J Expo Sci Environ Epidemiol

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The annual domestic use of pesticides is continually increasing, virtually ensuring that everyone is exposed to some level of pesticides on a regular basis through diet or environment. The potential developmental and physical adverse effects these chronic pesticide exposures have on children are of increasing concern. To adequately evaluate the potential adverse effects resulting from these exposures, accurate methods to measure the amount of the pesticide absorbed by the body must be developed. We have developed a sensitive method to measure the urinary metabolites of atrazine, diazinon, malathion, 2,4 -dichlorophenoxyacetic acid ( 2,4 -D ) , and certain synthetic pyrethroids in human urine. In our method, stable isotopically labeled analogues of the metabolites were spiked into the urine, which was subsequently extracted at both a neutral and acidic pH using organic solvents. The extracts were analyzed by highperformance liquid chromatography coupled with tandem mass spectrometry ( HPLC -MS / MS ) using atmospheric pressure chemical ionization. Our method has limits of detection ranging from 20 to 500 ng / l ( parts per trillion ) and relative standard deviations of less than 11%. This method has been used to measure the internal doses of these pesticides in both adults and children ( n = 130 ) with no documented exposure to the pesticides. We detected atrazine and synthetic pyrethroid metabolites in less than 12% of the samples analyzed. The metabolites of 2,4 -D, malathion, and diazinon were detected in 22%, 32%, and 57% of the samples, respectively. Journal of Exposure Analysis and Environmental Epidemiology ( 2000 ) 10, 789 ± 798.

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“…Many organophosphorus compounds have been listed in European Community (EC) and US Environmental Protection Agency (USE-PA) regulations governing drinking water quality and protection of the aquatic environment [6][7][8] and considerable effort has been devoted to determination of the levels of the organophosphorus pesticides in the environment. Because organophosphorus compounds are readily metabolized into alkyl phosphates in environmental and biological systems [9][10][11][12], the determination of low concentrations of alkyl phosphate metabolites has become an important issue in the accurate assessment of levels of exposure to organophosphorus compounds.…”

Section: Introductionmentioning

confidence: 99%

Determination of organophosphorus pesticide metabolites in surface water by use of a strong anion-exchange disk and in-vial derivatization

Chang

Lin

et al. 2000

Chromatographia

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SummaryDetermination of the metabolites of organophosphorus pesticides by means of a strong anion-exchange disk (SAX) and direct derivatization has been evaluated in this study. Five metabolites in water were extracted and concentrated by means of an SAX disk and then derivatized directly with methyl iodide in acetonitrile. Capillary column gas chromatography with flame photometric detection (GC-FPD) was used for quantification.Recoveries were approximately 76-96 % and were relatively stable throughout a broad pH range (6.5-12.0). The detection limits for these metabolites were approximately 0.021-0.12 #g L -~ for a 100-mL sample. Results from analysis of water samples collected from a fruit-growing area were indicative of the applicability of the method. Compared with methods reported in the literature, the method established in this study not only enables substantial simplification of sample preparation but also reduces the consumption of solvents during sample pretreatment. The method can be used to determine trace amounts of organophosphorus pesticides in surface waters to accommodate the increasing need for environmental monitoring.

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Method for the determination of dialkyl phosphate metabolites in urine for studies of human exposure to malathion

Cited by 38 publications

References 10 publications

Measurement of dialkyl phosphate metabolites of organophosphorus pesticides in human urine using lyophilization with gas chromatography-tandem mass spectrometry and isotope dilution quantification

Measurement of dialkyl phosphate metabolites of organophosphorus pesticides in human urine using lyophilization with gas chromatography-tandem mass spectrometry and isotope dilution quantification

Quantification of selected pesticide metabolites in human urine using isotope dilution high-performance liquid chromatography/tandem mass spectrometry

Determination of organophosphorus pesticide metabolites in surface water by use of a strong anion-exchange disk and in-vial derivatization

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