Liquid-Liquid Extraction of Insecticides from Juice: An Analytical Chemistry Laboratory Experiment

A laboratory experiment was developed to target analytical chemistry students and to teach them about insecticides in food, sample extraction, and cleanup. Micro concentrations (sub-mu g/mL levels) of 12 insecticides spiked into apple juice samples are extracted using liquid-liquid extraction and cleaned up using either a primary-secondary amine (PSA) cartridge or a C-18 cartridge. Extracts are then separated by gas chromatography and analyzed with tandem mass spectrometry. The method has been successfully tested by three. cohorts of quantitative analysis students to a determine the concentration of the insecticides spiked at 50 ng/mL in apple juice. Students' average recoveries were between 78 and 121% using C-18 cartridges (n = 30). Using PSA cartridges, average recoveries were between 47 and 121% (n = 6). Overall, this laboratory experiment was successful in teaching analytical chemistry students about environmental exposure to insecticides and sample processing.