SPE/GC-MS Determination of 2-Pyrrolidone, N-Methyl-2-pyrrolidone, and N-Ethyl-2-pyrrolidone in Liquid Pesticide Formulations

Pesticide adjuvants, chemicals with various toxicities, are added to pesticide formulations to improve their stability and efficacy. In the present study, an analytical method was developed for the simultaneous determination of the adjuvants, 2-pyrrolidone, N-Methyl-2-pyrrolidone, and N-Ethyl-2-pyrrolidone, in liquid pesticide formulations. Samples were diluted with ethyl acetate, purified using Oasis HLB as solid-phase extraction (SPE) cartridges, and analyzed by gas chromatography-mass spectrometry (GC-MS) using the external standard method. SPE in interferences retention mode was used herein and key parameters were optimized. Moreover, the necessity for the purification step was evaluated through comparison with direct measurement of diluted samples with no cleanup procedure. SPE was deemed necessary to remove contaminants from targets in liquid pesticide formulations with satisfactory accuracy and precision. The developed and validated SPE/GC-MS method is simple, accurate, and efficient for the simultaneous determination of the three polar adjuvants in complex liquid pesticide formulations.