Comparison of extraction methods and internal standards for the determination of benzo[a]pyrene in foods using liquid chromatography-tandem mass spectrometry

This study compared two extraction methods for determining benzo[a]pyrene in commonly consumed Korean foods using liquid chromatography-tandem mass spectrometry. Two internal standards, BaP- d ₁₂ and 3-methylcholanthrene (3MC), were evaluated for their quantitative performance. The first preprocessing method, incorporating saponification and liquid–liquid extraction, achieved recoveries of 87.2–113.4% and lower detection limits (0.019–0.055 ng/g), whereas the QuEChERS method yielded recoveries of 92.1–113.3% and higher detection limits (0.191–0.309 ng/g). BaP was detected in more food samples with the first preprocessing method, with mean concentrations ranging from 0.073 ± 0.126 ng/g (coke) to 1.817 ± 0.355 ng/g (crab), all below Korea’s regulatory limit of 2 ng/g. Evaluation of the internal standards revealed that both BaP- d ₁₂ and 3MC yielded consistent quantitative trends, although slight variations were observed in specific matrices due to differences in matrix composition and ionization behavior. Overall, both internal standards proved suitable for LC–MS/MS-based BaP analysis, and their selection should depend on availability, matrix characteristics, analytical context, and instrument optimization. These results confirm that validated extraction, combined with the use of appropriate internal standards, ensures accurate and reproducible BaP determination in various food matrices. • Two extraction methods were compared to determine BaP. • Alkaline saponification-LLE achieved a significantly lower LOD than QuEChERS. • Isotopic internal standard eliminated matrix-dependent bias observed with 3MC. • QuEChERS method provided satisfactory results in high-fat matrices.