Development and optimization of an effective method for the analysis of chloropropanols and their fatty acid esters in Chongqing hotpot base

Chloropropanols and their fatty acid esters, particularly 3-monochloropropane-1,2-diol (3-MCPD), are contaminants produced by heating in high-fat foods, such as Chongqing hotpot base, and pose reproductive toxicity and carcinogenicity risks. Their quantitative analysis is challenging due to the complex composition of oils and spices. Here, we developed a sensitive isotope dilution gas chromatography-mass spectrometry (ID-GC-MS) method with an optimized pretreatment process, including modified melting and filtration, refined nitrogen evaporation, and centrifugation after derivatization. This method demonstrated excellent linearity (R² ≥ 0.999), high recoveries (97.27–118.20 %), precision (RSD ≤ 14.93 %), and extremely low limits of detection and quantification (LODs and LOQs) (0.04–2.25 μg/L and 0.13–7.50 μg/L), surpassing previous methods. This method was applied to 12 hotpot base samples, and analysis of different production steps confirmed that processing temperature, time, and ingredients significantly influence the formation of chloropropanol esters. This validated method helps to systematically monitor and improve food safety. • Enhanced ID-GC-MS method for precise chloropropanol and ester quantification. • Optimized sample preparation for improved detection in Chongqing hotpot bases. • Temperature, time, and raw materials influence chloropropanol and ester formation. • Assessing health risks of chloropropanol exposure in the production of hotpot base.