The LC-MS/MS with Quick, Easy, Cheap, Effective. Rugged and safe method was used for analysis of eighteen pesticides in fruit samples. This method was found to be accurate (>= 99%), as it possessed limits of detection in the 0.002-0.087 ranges respectively. The coefficients of variations (>= 0.9999) were less than 2% at the low ng g(-1) concentration. Mean recoveries ranged between 97 and 101%, and % RSD were below 5%. The imidacloprid mean concentrations of red grapes (125.124 ng g(-1)) and green grapes (702.030 ng g(-1)) differed significantly (p < 0.05) between the grapes. Similarly, the fenitrothion mean concentration of red grapes (143.66 ng g(-1)) and green grapes (51.554 ng g(-1)) differed significantly (p < 0.001) between the fruits. The average concentration of quinalphos was 4.317 and 1.389 ng g(-1) differed significantly (p < 0.01) between the grapes. In apples imidacloprid, quinalphos, triazophos, ethion and acephate were also present. This study may be helpful in developing a regional exposure database and in the facilitation of health risk assessment due to pesticide exposure. (C) 2011 Elsevier Ltd. All rights reserved.

Organophosphorus (OP) insecticides were among the first pesticides that EPA reevaluated as part of the Food Quality Protection Act of 1996. Our goal was to assess exposure to OP insecticides in the U.S. general population over a six-year period. We analyzed 7,456 urine samples collected as part of three two-year cycles of the National Health and Nutrition Examination Survey (NHANES) from 1999-2004. We measured six dialkylphosphate metabolites of OP pesticides to assess OP pesticide exposure. In NHANES 2003-2004, dimethylthiophosphate was detected most frequently with median and 95th percentile concentrations of 2.03 and 35.3 mcg/L, respectively. Adolescents were two to three times more likely to have diethylphosphate concentrations above the 95th percentile estimate of 15.5 mcg/L than adults and senior adults. Conversely, for dimethyldithiophosphate, senior adults were 3.8 times and 1.8 times more likely to be above the 95th percentile than adults and adolescents, respectively, while adults were 2.1 times more likely to be above the 95th percentile than the adolescents. Our data indicate that the most vulnerable segments of our population-children and older adults-have higher exposures to OP pesticides than other population segments. However, according to DAP urinary metabolite data, exposures to OP pesticides have declined during the last six years at both the median and 95th percentile levels.

A sensitive method for the quantification of eight organophosphate pesticides in water samples at the ng L-1 concentration level has been developed. These organophosphates include pesticides, insecticides and herbicides used in agricultural applications. A lyophilization with simple solvent extraction followed by selective analysis using a liquid chromatography-mass spectrometry method was used. This method was accurate (>= 98.9%), as it possessed limits of detection and quantification in the 4.9-51 and 16.5-171 ng L-1 ranges, respectively. Furthermore, the coefficients of variations (>= 0.999) were less than 8.2% at the low ng L-1 end of the linear range of the method. In addition, the percentage recovery of all pesticides at the 0.1 mu g L-1 levels ranged from 96% to 103%. This method was then used for the quantification of organophosphates in drinking and bore water samples collected from different parts of urban areas. We subsequently found detectable levels of monocrotofos, imedacloprid, triazofos, atrazine, propanil, quinolfos and metribuzin in more than 23% of the water samples analyzed. (C) 2010 Elsevier B.V. All rights reserved.

Organophosphorus (OP) pesticides kill by disrupting a targeted pest's brain and nervous systems. But if humans and other animals are sufficiently exposed, OP pesticides can have the same effect on them. We developed a fast and accurate high-performance liquid chromatography-tandem mass spectrometry method for the quantitative measurement of the following six common dialkylphosphate (DAP) metabolites of organophosphorus insecticides: dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate (DMDTP), diethylphosphate, (DEP), diethylthiophosphate (DETP), and diethyldithiophosphate (DEDTP). The general sample preparation included 96-well plate solid phase extraction using weak anion exchange cartridges. The analytical separation was performed by high-performance liquid chromatography with a HILIC column. Detection involved a triple quadrupole mass spectrometer with an ESI probe in negative ion mode using multiple reaction monitoring. Repeated analyses of urine samples spiked at 150, 90 and 32ng/mL with the analytes gave relative standard deviations of less than 22%. The extraction efficiency ranged from 40% to 98%. The limits of detection were in the range of 0.04-1.5ng/mL. The throughput is 1152 samples per week, effectively quadrupling our previous throughput. The method is safe, quick, and sensitive enough to be used in environmental and emergency biological monitoring of occupational and nonoccupational exposure to organophosphates.