Development and Validation of a Residue Analysis Method for Ethylene Oxide and 2-Chloroethanol in Foods by Gas Chromatography Tandem Mass Spectrometry

A selective and sensitive method is reported for the residue analysis of ethylene oxide (EO) in diverse matrices, namely sesame, cumin, wheat, tea, spices, herbs, dehydrated fruits, food additives, grapes, and tomatoes. The study modified the European Union reference method (EN 15662) by performing the sample extraction (with acetonitrile) at <10 °C, cleanup through dispersive-solid phase extraction with C18 and primary secondary amine sorbents, and analysis using gas chromatography tandem mass spectrometry with selected reaction monitoring. Injections were performed through a programmable temperature vaporizer port. The sample preparation process provided a limit of quantification of 10 ng/g for both EO and 2-CE and effectively minimized matrix effects. Recoveries of both EO and 2-CE ranged from 74 to 120% at 10, 20, and 50 ng/g with precision RSDs of <12%, satisfying the SANTE/11312/2021 guidelines of analytical method validation. The HorRat (Horwitz ratio) values of 0.31–0.40 indicated high interlaboratory (n = 6 laboratories) method reproducibility. The results of incurred residues in sesame (0.055–0.1 mg/kg), cumin (0.008–0.013 mg/kg), and coriander (0.01–0.025 mg/kg) demonstrated satisfactory extraction efficiency and precision (RSDs < 10%) in test results. The method is highly suitable for regulatory analysis of EO in diverse food matrices.