Development of a Detection Method for Quaternary Ammonium Compounds in Foods and Its Application to Commercial Foods and Dietary Samples in Beijing

An analytical method based on ultra-high performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous detection of nine commonly used quaternary ammonium compounds (QACs) in various food matrices including vegetables, fruits, and aquatic products. The enrichment and purification of QACs were achieved using an improved quick, easy, cheap, effective, rugged and safe (QuEChERS) method, and the separation was performed on a BEH C₁₈ column (100 mm × 3.0 mm, 1.7 μm) with gradient elution. QACs were detected using an electrospray ionization source in the positive ion mode. The limits of detection and quantification for the nine QACs in vegetables, fruits, and aquatic products were 0.2–5.0 and 1.0–10.0 μg/kg, respectively, and good linearity was observed for all analytes within their respective concentration ranges (R² > 0.99). The recoveries for spiked samples were in the range of 65.24%–118.63% with relative standard deviations (RSDs) of 0.19%–6.77%. When the developed method was applied to commercial foods and dietary samples in Beijing, detection rates of 30.43% and 12% were obtained, respectively. The dietary risk of QAC residues was acceptable.