液相色谱-串联质谱法检测食用油中辣椒碱类化合物

Determination of capsaicinoids in edible oil by liquid chromatography-mass spectrometry

目的建立液相色谱-串联质谱法检测食用油中辣椒碱类化合物(包括天然辣椒碱、合成辣椒碱、二氢辣椒碱)的分析方法。方法通过对固相萃取柱、色谱条件和质谱条件的优化,最终确定了以中性氧化铝小柱富集目标物进行样品的前处理,经Agilent SB-C_(18)色谱柱(100 mm×2.1 mm, 1.8μm),以乙腈和0.1%甲酸水作为流动相,等度洗脱,柱温40℃,流速0.3mL/min,多反应监测模式进行检测。结果最优条件下,目标物的回收率达80%以上,天然辣椒碱、合成辣椒碱和二氢辣椒碱的检出限均为0.15μg/kg,定量限均为0.5μg/kg,在一定的浓度范围内线性关系良好(r^2>0.999)。结论本方法具有检出限低、回收率高、结果稳定、重现性高等优点,通过对实际样品的检测,可作为筛查和鉴定地沟油的有效方法之一。

Objective To establish a method for the determination of capsaicinoids （including natural capsaicinoids, synthetic capsaicinoids and dihydrocapsaicinoids） in edible oils by liquid chromatography-mass spectrometry （LC-MS/MS）. Methods By optimizing the conditions of solid-phase extraction column, chromatography and mass spectrometry, the pretreatment of samples was finally determined by enriching the target with neutral Al2O3 solid phase extraction column. The samples were separated by a Agilent SB-C18 column （100 mm×2.1 mm, 1.8 μm） at the flow rate of 0.3 mL/min by gradient elution with acetonitrile and 0.1% formate water as mobile phase. The temperature of the column oven was maintained at 40 ℃. The detection was carried out by multi-reaction monitoring. Results Under the optimal conditions, the recovery rate of the targets was up to 80%, the limits of detection of natural capsaicinoids, synthetic capsaicinoids and dihydrocapsaicinoids were 0.15 μg/kg, and the limits of quantitative were 0.5 μg/kg. The linear relationship was good in a certain concentration range （r2〉0.999）. Conclusion This method has lower detection limit, higher recovery rate, higher stability and reproducibility, which can be used as one of the effective methods to screen and identify the illegal cooking oil through the test to the actual sample.