GC法测定打蜡苹果中非法添加物质工业石蜡指标性成分的含量

Determination of Industrialparaffin’s Index Componentsillegally Added into Apples by Gas Chromatography

目的建立气相色谱法检测打蜡苹果中非法添加物质工业石蜡指标性成分正二十二烷、正二十八烷含量的分析方法。方法苹果果皮匀浆样品经正己烷提取、旋转蒸发仪减压浓缩后,加入2mL浓硫酸净化处理,所得正己烷提取液经0.22μm微孔滤膜过滤后进气相色谱仪进行测定。结果通过对样品中正二十二烷、正二十八烷两种工业石蜡指标性正构烷烃的测定,正二十二烷回收率为84.2%~88.9%,相对标准偏差(RSD)为6.2%~7.3%,检出限为2.5mg/kg,定量限为3.9mg/kg;正二十八烷回收率为85.4%~89.5%,相对标准偏差(RSD)为6.3%~7.1%,检出限为2.3mg/kg,定量限为3.7mg/kg。结论该方法专属性强、灵敏度高、定量准确,能满足于苹果果皮中非法添加石蜡的检测。

Objective: To establish a gas chromatography (GC) method for the determination of n-Docosane and n- Octacosane,which were the index components of industrial paraffin illegally added into apples.Methods: The samples were extracted with hexane and purified by 2 mL of sulfuric acid.The analytes were filtered by 0.22μm membrane filter,and tested by GC.Results: The determination results of n-Docosane and n-Octacosane showed that the recoveriesof n-Docosane and n-Octacosane were84.2 %~88.9 % and 85.4 %~89.5 %,and the relative standard deviations were 6.2 %~7.3 % and6.3 %~7.1 %separately. Besides,The limit of detection( LOD) and the limit of quantitation( LOQ) on n-Docosane were 2.5 mg/kg and 3.9 mg/kg,and the LOD and LOQ of n-Octacosane were 2.3 mg/kg and 3.7 mg/kg.Conclusion: The GC method was suitable for the determination of paraffin added illegally in apples,which had a better performance on specificity,sensitivity and quantification.