Development and Validation of a Method for the Determination of Pesticide Residues in Beer by Liquid Chromatography–Mass Spectrometry

Research into the fate of pesticides utilized in the commercial production of hops and their subsequent usage in the brewing of beer was conducted. To address the quantitation of pesticides, an analytical method was developed for the multiresidue determination of pesticides in beer. The method utilized acidified acetonitrile extraction with salt-aided liquid-liquid partition, centrifugation, and determination by liquid chromatography with tandem mass spectrometry using positive mode electrospray ionization. Validation of the method occurred at the Pacific Agricultural Laboratory (Portland, OR) and the Trace Analytical Laboratory (University of California, Davis, CA). Method validation recoveries from control beer samples generally ranged from 70 to 120% over three levels of fortification (0.5, 1.0, and 10 ng/mL) with relative standard deviations <20%. The limit of quantitation for beer was 0.5 ng/mL, and the calculated method detection limit ranged from 0.0240 to 0.322 ng/mL.