气相色谱-质谱联用法测定奶粉中的三聚氰胺

目的]建立奶粉中三聚氰胺的气相色谱-质谱(GC-MS)测定方法。方法]利用三乙胺、水、甲醇超声萃取样品中的三聚氰胺,结合气相色谱-质谱法对奶粉中三聚氰胺进行测定。结果]使用三乙胺/去离子水/甲醇混合液对奶粉中的三聚氰胺进行提取后,进一步采取硅烷化衍生法,有效地去除了基质所带来的干扰,而在前处理中加入苯代三聚氰胺做内标显著地提高了方法的精密度。在0.1～50.0 mg/L范围内呈现良好的线性关系,最低检测限为0.1μg/g,添加奶粉中的三聚氰胺回收率在102.0%～104.2%,相对标准偏差为4.2%。结论]该方法可满足奶粉中三聚氰胺的准确定性和定量测定要求。

Determination of Melamine in Powdered Milk by Gas Chromatography-Mass Spectrometry

Objective]A gas chromatography-mass spectrometry(GC-MS) method was developed for the determination of melamine in powdered milk.Method] The melamine was extracted from the milk samples with the triethylamine-methanol-deionized water solution and then determined by the GC-MS method.Result] The milk sample was extracted with triethylamine-methanol-deionized water solution and derivatized with N,O-bis(trimethylsilyl) trifluoroacetamide(BATFA),which effectively decreased the influence casued by the matrix.The adding of benzoguanamine as internal standard in the preceding process could significantly improve the precision of the method.The linear range was from 0.1 to 50.0 mg/L.The limits of detection were 0.1 μg/g.The average recoveries were 102.0%-104.2% for melamine in powdered milk sample,and the relative standard deviations were less than 4.2%.Conclusion] The method is suitable for the qualitative and quantitative determination of melamine in milk.