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目的建立食用油脂中特征脂肪酸的气相色谱-质谱联用检测方法并评估特征脂肪酸鉴别餐厨废弃油脂的有效性。方法采集植物油混合地沟油22份、煎炸老油20份、纯精炼地沟油7份、植物原油9份、精炼植物油48份、棕榈油6份、正常食用油加香精5份,油样经甲酯化处理后,采用UF-m FFAP毛细管气相色谱柱(30 m×0.25mm,0.25μm),经气相色谱-质谱法检测样品中十一烷酸甲酯和13-甲基十四烷酸甲酯的含量,对检测结果以样品类别进行统计学检验,评估特征脂肪酸鉴别废弃油脂的有效性。结果通过特征脂肪酸指标鉴别地沟油的方法是有效的。13-甲基十四烷酸可选为是否含有动物源性油脂的指标物,十一烷酸可选为反复煎炸油脂的指标物。两者结合可为鉴别正常植物油和餐厨废弃油提供有利依据。结论特征脂肪酸检测灵敏度高,特异性较强,但由于地沟油基本都是勾兑正常植物油出售,判定结果会出现假阴性,需结合其他指标进行研判,以提高鉴别的有效性。
Objective To establish a gas chromatography-mass spectrometry (GC-MS / MS) method for the determination of fatty acids in edible oils and to evaluate the effectiveness of edible fatty acids in the identification of kitchen waste oils. Methods Twenty-two parts of vegetable oil mixed waste oil, 20 parts of fried old oil, 7 parts of pure refined waste oil, 9 parts of vegetable crude oil, 48 parts of refined vegetable oil, 6 parts of palm oil, 5 parts of normal edible oil and flavoring agent, After esterification, UF-m FFAP capillary gas chromatography (30 m × 0.25 mm, 0.25 μm) was used to determine methyl undecanoate and 13-methyltetradecanoic acid methyl ester in the sample by gas chromatography-mass spectrometry Ester content, the test results were tested by the sample category statistics to assess the effectiveness of fatty acids identified waste oil. As a result, the method of identifying the waste oil by the characteristic fatty acid index is effective. 13-methyl-tetradecanoic acid is optional as an indicator of animal-derived oils and fats, undecanoic acid can be selected as an indicator of repeated frying fat. The combination of the two can provide a good basis for identifying normal vegetable oil and kitchen waste oil. Conclusion The detection of characteristic fatty acids is highly sensitive and specific. However, due to the fact that the cooking oil is basically sold under the normal vegetable oil, the false negative results will be found, which need to be combined with other indicators to improve the effectiveness of identification.