基于稳定碳同位素示踪技术的商品植物油掺杂鉴别研究

Discrimination of the Adulteration of Commercial Vegetable Oils by Stable Carbon Isotope Analysis

摘要:

本文旨在运用所建立的纯植物油的脂肪酸组成及其稳定碳同位素比值判别标志对广州市售商品植物油是否掺杂进行判识。先在广州某大型超市购得18种商品植物油(包括3种茶籽油、5种花生油、2种葵花油、2种玉米油和6种橄榄油)；然后采用气相色谱-质谱联用仪（GC-MS）、气相色谱-同位素比值质谱仪（GC-IRMS）和元素分析-同位素比值质谱仪（EA-IRMS）对这18种商品油的脂肪酸组成和全油及其脂肪酸的稳定碳同位素比值进行测定；最后将本次检测所获得的数据与作者之前建立的判别标志进行对比分析。对比结果表明，本批商品植物油的品质总体较好，但其中50%的植物油商品存在掺杂。因此，将植物油脂肪酸组成数据与其稳定碳同位素比值数据相结合，可灵敏地确定待检植物油是否存在掺杂。

Abstract:

This paper aims to develop a new discrimination method for the adulteration of commercial edible vegetable oils from Guangzhou market by previously-established markers of fatty acid composition and stable carbon isotope ratios. 18 vegetable oils, including camellia oil, peanut oil, sunflower oil, maize oil and olive oil were purchased from the supermarket in Guangzhou. Then, their fatty acid compositions were determined by chromatography mass spectrometry (GC-MS); the stable carbon isotope ratios (?13C) of bulk oil samples and their individual major fatty acids were determined by elemental analysis-isotope ratio mass spectrometry (EA-IRMS) and gas chromatography-isotope ratio mass spectrometry (GC-IRMS). The measured data were compared with previously-reported discrimination markers. The results indicated that the quality of the commercial vegetable oils from market was overall high, but the adulteration still occurred in 50% of the samples. Obviously, the adulteration of vegetable oils may be sensitively discriminated by the markers of stable carbon isotope ratios and fatty acid composition.