关键词: 肉制品, 胆固醇氧化物, 室温皂化, 7-酮基胆固醇, 气相色谱-高分辨-飞行时间质谱

Abstract: In view of the diverse forms and unstable properties of cholesterol oxides (COPs) in meat products, a room temperature saponification pretreatment technology was established, which combined with the advantages of gas chromatogravimetry, high resolution and time-of-flight mass spectrometry to achieve comprehensive and accurate detection of 9 cholesterol oxides in meat products. The results showed that chloroform: methanol (v:v 2:1) was extracted, saponification at room temperature for 18h, ethyl acetate: n-hexane (v:v 80:20) Extraction and amino-solid phase extraction column purification were the optimal pre-treatment conditions. The linear range of 7α-hydroxyl cholesterol and 7β-hydroxyl cholesterol detection was 0.002~0.5 μg/mL. The linear range of 5β, 6β-epoxide cholesterol,5α, 6α-epoxide cholesterol, 20α-hydroxy cholesterol, 3β,5α, 6β-trihydroxy cholesterol, 25α-hydroxy cholesterol, 7-keto cholesterol and 27α-hydroxy cholesterol was 0.02 μg/mL~0.5 μg/mL. The determination coefficients were all ≥0.9990, the detection limit was 0.0001-0.001 mg/kg, and the quantitation limit was 0.0002-0.002 mg/kg. The method has good accuracy and high precision. The average recoveries of samples are 89.7% ~ 116.1%, and the relative standard deviations are less than 8.7%. Compared with high temperature saponification, room temperature saponification can effectively prevent the autoxidation of cholesterol and the degradation of 7-ketocholesterol, reduce the exogenous introduction and endogenous loss of target substances, and realize the rapid and accurate detection of 9 kinds of COPs.

Key words: meat product, cholesterol oxide, saponification at room temperature, 7-keto cholesterol, gas chromatography-High resolution-time-of-flight mass spectrometry