Source identification of vanillin in sesame oil by HPLC-MS/MS

Recently, we found that vanillin commonly exists in sesame oils, while vanillin compounds are not allowed to be used as food additives in edible vegetable oils according to Chinese standards for Food Additives (GB2760-2014). To trace the source of vanillin in sesame oil, an accurate and reliable method was developed and validated for the determination of vanillin, methyl vanillin and ethyl vanillin in sesame samples based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The limit of determination (LOD) and limit of quantification (LOQ) of the established method were in the range of 17.4–33.1 and 52.2–99.2 μg kg−1, respectively. The calibration curves of the three vanillin compounds exhibited good linearity between 0 and 400 ng mL−1, with a high correlation coefficient greater than 0.999. The recoveries ranged from 91.7% to 112%, with a low relative standard deviation (RSD) less than 5.55%. Then this method was applied for the detection of sesame seed and intermediate samples. The results showed that all samples contained vanillin in a concentration range of 382–3804 μg kg−1, while methyl vanillin and ethyl vanillin were not detected in those samples. Hence, the vanillin in sesame oil may originate from its raw materials, indicating that vanillin was not a good detection marker for illegal addition of flavor enhancers in sesame oils.