Analysis of polychlorinated alkanes in food by liquid chromatography–tandem mass spectrometry

Polychlorinated alkanes (PCAs), the principal constituents of chlorinated-paraffin technical mixtures, are persistent, bioaccumulative pollutants that raise growing toxicological concern. Due to their complexity, PCA analysis in food remains analytically challenging, predominantly relying on high-resolution mass spectrometry applications. This study aimed to develop and validate a more accessible liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for quantifying PCA-C 10–17 in food commodities. Six reversed-phase columns were evaluated during the study, and phenyl-hexyl and biphenyl stationary phases provided superior separation of critical isobaric PCA homologues. Ammonium acetate (5 mM) was used as a mobile phase additive to promote the formation of acetate adducts, enhancing selectivity in MS/MS settings by minimizing the impact of deprotonated species on product-ion spectra. Validation experiments conducted using fortified samples demonstrated satisfactory recoveries (PCA-C 10–13 , 88%; PCA-C 14–17 , 121%; and PCA-C 10–17 , 103%). Comparative analyses using six interlaboratory test materials and a certified fish matrix reference material confirmed the method’s accuracy. All z -scores for PCA-C 10–13 were ≤|2|, and only 2 results for PCA-C 14–17 were in the questionable range (| z |= 2–3). In the certified reference material, measured values for PCA-C 10–13 were within the certified range, while those for PCA-C 14–17 were near its lower boundary. The developed method was compared to the conventional high-resolution mass spectrometry, showing a strong agreement between the results of both instrumental setups. These results establish this LC–MS/MS protocol as an accessible and reliable alternative to PCA monitoring within food safety and regulatory frameworks.