A Quantitative Tandem Mass Spectrometry and Scaled-Down QuEChERS Approach for Simultaneous Analysis of Pesticide Multiresidues in Human Urine.

Multiresidual pesticide determination in a biological sample is essential for an immediate decision and response related to various pesticide intoxications. A rapid and simultaneous analytical method for 260 pesticides in human urine was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). High speed positive/negative switching electrospray ionization (ESI) mode was used, and scheduled multiple reaction monitoring (MRM) was optimized. Three versions of scaled-down QuEChERS procedures were evaluated, and the procedure using non-buffer reagents (magnesium sulfate and sodium chloride) and excluding cleanup steps was selected for optimum pesticide extraction. The limit of quantitation (LOQ) in this methodology was 10 ng/mL for each target pesticide, and correlation coefficient (r²) values of calibration curves were ≥0.988 (linearity range; 10-250 ng/mL). In accuracy and precision tests, the relative error ranges were -18.4% to 19.5%, with relative standard deviation (RSD) 2.1%-19.9% at an LOQ level (10 ng/mL), and -14.7% to 14.9% (RSD; 0.6%-14.9%) at higher concentrations (50, 150, and 250 ng/mL). Recovery range was 54.2%-113.9% (RSD; 0.3%-20.0%), and the soft matrix effect (range; -20% to 20%) was observed in 75.4% of target pesticides. The established bioanalytical methods are sufficient for application to biomonitoring in agricultural exposures and applicable in the forensic and clinic.