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建立了食用油中脂肪酸组成的在线水解甲基化-气相色谱测定方法,分析了20余种常用食用油与非正常食用油样品。将1μL(3 mg/mL)油脂样品与2μL衍生化试剂四甲基氢氧化铵(TMAH,25%甲醇溶液)加入裂解器,在350℃下,油脂加水分解瞬间衍生化成相应的脂肪酸甲酯。基于气相色谱图上分离鉴定到的10个共有峰的相对强度,建立了食用油的气相色谱指纹图谱。结合化学模式识别即主成分分析和系统聚类分析对合格食用油和非正常食用油样品的色谱图进行了识别分析。结果表明,建立的指纹图谱结合模式识别技术可以较好的区分合格食用油与非正常食用油样品。
A method for the determination of fatty acids in edible oil by on-line hydrolysis-methylation-gas chromatography was established. More than 20 kinds of commonly used cooking oil and non-normal cooking oil samples were analyzed. A sample of 1 μL (3 mg / mL) oil and 2 μL of derivatization reagent, tetramethylammonium hydroxide (TMAH, 25% methanol solution), were added to the pyrolyzer to derivatize the corresponding fatty acid methyl ester instantly at 350 ° C. Based on the relative intensities of the 10 common peaks isolated and identified on the gas chromatogram, a gas chromatographic fingerprint of edible oil was established. Combined with chemical pattern recognition, ie, principal component analysis and cluster analysis, the chromatograms of qualified and non-normal cooking oil samples were identified and analyzed. The results show that the established fingerprint and pattern recognition technology can better distinguish between normal cooking oil and non-normal cooking oil.