非正常食用油鉴别新方法（二）：特征奇数碳脂肪酸的多维气相色谱-质谱检测

Endogenesis referents from illegal cooking oil (ICO), namely, 13-methyl-tetradecanoic acid and undecanoic acid have been confirmed via non-target and target screening of fatty acids. The former is mainly originated from animal oil, and the later from heated vegetable oil. Based on the retention interactions between gas chromatographic columns with different polarities and alkyl acids, the alkyl acids with various carbon chain or their isomers with the same carbon chains can be separated effectively using multidimensional gas chromatographymass spectrometry. And the accurate quantification of 13-methyl-tetradecanoic acid and undecanoic acid was obtained. The target compounds can be cleaned up online and enriched with the developed method. Subsequently, the fourth and fifth assessments organized by China National Center for Food Safety Risk Assessment were performed in our laboratory. After continuous improvement, the precision of the method was increased. In detail, 100% vegetable oils, 71% ICO (the 4th batch) and 75% ICO (the 5th batch) have been identified. In combination with the capsaicinoid contents, edible oils can be identified in a comprehensive way, and the precision for ICO samples was increased to 89% and 100% for the 4th batch and the 5th batch samples, respectively. Owing to the aforementioned advantages, the developed method has been chosen as one of the four instrumental methods for the identification of ICO by China Ministry of Public Health, waiting for the validation from authoritative departments.