气相色谱法测定食品中山梨酸、苯甲酸的改进

目的建立食品中山梨酸、苯甲酸检测方法并对其前处理进行合理的改良。方法样品经盐酸酸化,用乙醚提取,接着用氯化钠酸性溶液洗涤2次后将提取液转入无水硫酸钠溶液中蒸发近干,残渣用丙酮溶解;用色谱柱分离,具氢火焰离子化检测器进行检测。结果本法山梨酸和苯甲酸相对偏差分别为3.71%和2.11%;加标回收率分别为87.0%-95.2%和97.0%-103.1%,远远高于国标法中的回收率。结论本方法样品前处理操作简单方便,准确度和灵敏度高,适用于食品中山梨酸、苯甲酸的测定。

Modified gas chromatographic method for the determination of sorbic acid, benzoic acid in food

Objective To establish a method of sorbic acid,benzoic acid in food and improve pretreatment.Method The sample was extracted with ether after hydrochloric acid was added.Washing the extracted liquid by sodium chloride solution two times,then transferring to the anhydrous sodium sulfate solution and evaporating the solution nearly dry.Finallly the residue was dissolved by acetone.Seperation with column chromatography,detected in hydrogen ionizaed flame.Results RSDs of sorbic acid and benzoic acid were 3.71% and 2.11%,then the rate of recovery were 87.0%-95.2% and 97.0%-103.1% respectively.Both of them are better than the indices in national standard method.Conclusion The pretreatment of sample is simple and convenient.The method is with good accuracy and precious,and suitable for the analysis of sorbic acid,benzoic acid in food.