气相色谱-质谱法测定奶粉中的三聚氰胺

对气相色谱-串联质谱(GC-MS/SIM)测定奶粉中三聚氰胺质量分数的分析方法进行了改进.色谱柱为DB-5MS石英毛细管柱,进样口温度260℃,柱温120℃,保持1 min,再以20℃/min升至240℃,恒温10 min.载气He,流量1.0 mL/min.EI离子源,选择m/z99,171,327,342用于三聚氰胺定性测定,以基峰m/z 327做定量测定.三聚氰胺的线性范围为0.2～1 mg/kg,平均回收率为82%～97%,检出限为1μg/kg,定量下限为5μg/kg.该方法比现有国标方法更加快速和灵敏,适合于三聚氰胺准确、快速检测.

Determination of melamine in milk powder by GC-MS

The method for determination of melamine in milk powder by gas chromatography-mass spectrum with selected ion monitor(GC-MS/SIM)was improved.DB-5 MS quartz capillary column was used with optimized working conditions of He carrier gas rate at 1.0 mL/min,injector tempreture at 260℃ and column temperature keeping 1 min at 120℃,heating rate 20℃ /min to 240℃.The conditions for GC-MS were optimized,and the ions elected were m/z 99,171,327,342.Qualitative determination was acquired by the four characteristic ions and retention time,and quantitative determination was achieved using base peak m/z 327.The linear range was 0.2～1 mg/kg,and the average recovery of melamine was in the range of 82%～97% with detection limit as 1μg/kg and quantification limits was 5μg/ kg.The method was more rapid and sensitive than GB method which suitable to the accurate and rapid determination of melamine in milk powder with satisfactory results.