气相色谱-质谱联用法测定奶粉中苯甲酸(钠)含量

Determining benzoic acid in powdered milk by GC-MS

目的：建立测定奶粉中苯甲酸（钠）含量的新方法。方法：奶粉样品溶于水后,经去蛋白、过滤、调节pH值,苯甲酸经二氯甲烷提取,用气相色谱-质谱联用仪测定其含量。结果：苯甲酸加标回收率为80.5%-101.0%,其相对标准偏差（RSD）为1.65%-3.82%,最低检出限为0.45 mg/L。结论：本方法步骤简单、结果准确可靠、灵敏度高,适合奶粉中苯甲酸（钠）含量的测定。

Objective：To develop a method to determine benzoic acid in powdered milk by GC-MS.Methods：After being dissolved by water and depositing protein,the powdered milk samples were filtered and the pH of solution was adjusted.Benzoic acid was extracted by dichloromethane and analyzed by GC-MS.Results：The average recovery rate was 80.5%～101.0%.The relative standard deviation range of samples added standard substance was 1.65%～3.82%.The detection limit was 0.5 mg/kg.Conclusion：The method is simple,rapid,reliable and accurate.It is suitable for the detection of benzoic acid in powdered milk.