Multiresidue extraction of current-use pesticides from complex solid matrices using energized dispersive extraction with analysis by gas and liquid chromatography tandem mass spectroscopy

A multiresidue method for solids (i.e., soil, sediment, sludge) was developed and evaluated for the analysis of pesticides and pesticide degradates. Initially, a well characterized soil was used to determine the recovery of target compounds using an Energized Dispersive Guided Extraction (EDGE) system with two extraction solvents, acetonitrile and 1:1 (v/v) hexane:acetone. Extracts were cleaned using solid-phase extraction (SPE) with graphitized carbon cartridges and three elution solvents, acetonitrile, dichloromethane, and 1:1 (v/v) dichlormethane:ethyl acetate. The individual SPE elutions from the two extraction solvents were analyzed separately via GC-MS/MS and LC-MS/MS for 210 pesticides and pesticide transformation products. Ultimately, the acetonitrile extraction solvent on the EDGE system combined with SPE carbon cleanup with sequential acetonitrile and dichloromethane elutions resulted in extraction recoveries between 70% and 130% for 167 analytes. Recoveries were compared to a previously validated pressurized liquid extraction (PLE) method. The EDGE method was used to analyze field soil (n=2), sediment (n=5), and biosolids (n=2) samples. A strong 1:1 linear correlation (R^2>0.999) was observed between measured concentrations of the two extraction methods. The limits of detection for 5 g samples ranged from 0.09 to 2.56 ng/g.