A Multiresidue Method for the Analysis of Pesticides in Water using Solid-Phase Extraction with Gas and Liquid Chromatography-Tandem Mass Spectrometry

Application of pesticides in agricultural and urban settings plays an essential role in increasing crop yields, preserving food and materials, reducing pest-borne diseases, and eradicating or deterring pests. Pesticides are transported from their point of application to environmental media, including surface water and groundwater. To better understand the fate of fate and transport of pesticides in the environment, analytical methods are necessary to measure pesticides in waters. Herein, an analytical method is described for the extraction and analysis of 184 pesticides and degradates in water. Water samples (~ 1 L) are filtered using 0.7 μm glass-fiber filters prior to being extracted and concentrated using hydrophilic-lipophilic balance (HLB) cartridges. Analysis is completed using liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography tandem mass spectrometry (GC-MS/MS). Analyte recoveries were 60-109%, with an average recovery of 89%. The method showed great reproducibility with an average relative standard deviation (RSD) less than 5%. Limits of detection (LODs) and reporting limits (RLs) ranged from 0.5-10 ng/L and 1.5-30 ng/L, respectively. The analytical method will be applied toward the analysis of pesticides and degradates in water samples from around the United States.