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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/m L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。
Objective To establish a method for the determination of stearic acid in two kinds of foodstuffs to understand the content of stearic acid in food and to compare the two methods. Methods The samples were extracted by methyl esterification and analyzed by gas chromatography (GC) and gas chromatography tandem mass spectrometry (GC-MS). Results GC and GC-MS showed a good linearity in the range of 5 ~ 500 mg / L and 0.05 ~ 1 mg / mL, respectively. The correlation coefficient R2 was greater than 0.99. GC method by subtracting the background value of the method, the 1.0,1.2 and 1.5 mg / kg at three concentrations of the recovery ranged from 77.6% to 93.8%, the relative standard deviation of less than 12%, the detection limit and the limit of quantification were 3.3 mg / kg and 10.0 mg / kg. The recoveries of GC-MS at three concentrations of 0.2, 0.25 and 0.3 mg / kg ranged from 83.8% to 102.9% and the relative standard deviation was less than 10%. The detection limits and the limits of quantification were 0.06 mg / kg and 0.2 mg / kg. The results of the two methods were calculated by linear regression, the correlation coefficient was 0.9949, there was no significant difference between the two results. Conclusion The two methods have good repeatability and sensitivity to meet the domestic and foreign requirements for the determination of stearic acid in food, which can be used for quantitative analysis of a large number of samples.