Analysis of Pesticides in Plant Foods by QuEChERS and Gas Chromatography–Mass Spectrometry: An Undergraduate Laboratory Experiment

Undergraduate students in an environmental chemistry laboratory course were taught QuEChERS (quick, easy, cheap, effective, rugged, and safe), a sample preparation procedure that is commonly used in pesticide laboratories involving an acetonitrile salt-out extraction of fresh produce samples followed by solid-phase dispersive cleanup using a combination of sorbents. The cleaned extract was solvent exchanged into toluene and analyzed for pesticides by capillary gas chromatography–mass spectrometry in selective ion monitoring mode (GC–MS/SIM). Students utilized QuEChERS to analyze spiked and incurred pesticide residues in several types of plant foods and applied GC–MS/SIM for the simultaneous quantitation and identification of pesticides. Several chemistry, laboratory, and instrumental concepts were demonstrated such as sample preparation, aspects of method validation, and interpretation of chromatographic and mass spectrometric results. This experiment received favorable responses from the students because...