食品中硬脂酸的测定

Determination of stearic acid in foodstuffs

中文关键词:  食品  气相色谱法  气相色谱串联质谱法  硬脂酸

英文关键词:food  gas chromatography  gas chromatography-mass spectrometry  stearic acid

中文摘要:

      目的 建立两种食品中硬脂酸含量测定的方法, 以了解食品中硬脂酸的含量, 并对两种测定方法进行比较。方法 样品经提取脂肪后进行甲酯化衍生, 采用气相色谱法(GC)和气相色谱串联质谱法(GC-MS)进行定量分析。结果 GC法和GC-MS法分别在5~500 mg/L和0.05~1 mg/mL范围内线性良好, 相关系数R2大于0.99。GC法通过扣除本底值的方法, 在1.0、1.2和1.5 mg/kg三个添加浓度上回收率范围为77.6%~93.8%, 相对标准偏差小于12%, 方法检出限和定量限分别为3.3 mg/kg和10.0 mg/kg。GC-MS法在0.2、0.25和0.3 mg/kg三个添加浓度上回收率范围为83.8%~102.9%, 相对标准偏差小于10%, 方法检出限和定量限分别为0.06 mg/kg和0.2 mg/kg。两方法测定的结果经计算线性回归, 相关系数为0.9949, 两结果不存在显著差异。结论 两种方法重复性好, 灵敏度满足国内外对食品中硬脂酸的检测要求, 可用于大量样品的定量分析。

英文摘要:

      Objective Two methods for the determination of stearic acid were developed in order to realize the content of stearic acid in foodstuffs. Methods Samples were determined by Gas Chromatography and Gas Chromatography-Mass Spectrometry after extracting the fat and methyl esterfying. Results The method of GC showed the recoveries of stearic acid were between 77.6% and 93.8% with the relative standard deviations (RSDs) less than 12% at three spiked levels of 1.0, 1.2 and 1.5 mg/kg. The limit of detection (LOD) and the limit of quantification (LOQ) were 3.3 mg/kg and 10.0 mg/kg respectively. The method of GC-MS showed the recoveries of stearic acid were between 83.8% and 102.9% with RSDs less than 10% at three spiked levels of 0.2, 0.25 and 0.3 mg/kg. The LOD and the LOQ were 0.06 mg/kg and 0.2 mg/kg. The correlation coefficient was 0.9949 through regression test to the results of the two methods. Therefore, there was no significant difference between the two results. Conclusion The repeatability and sensitivity satisfies the requirement of stearic acid in food detection and can be used in a large number of samples for quantitative analysis.