气相色谱-质谱法快速测定乳粉中三聚氰胺

Rapid determination of melamine in milk powder by gas chromatography-mass spectrometry

目的：建立气相色谱-质谱法测定乳粉中三聚氰胺含量的分析方法。方法：样品经乙酸-乙腈-水溶液超声提取,离心,滤液经混合型阳离子交换固相萃取柱净化,氮气吹干,硅烷化衍生,气相色谱-质谱测定,选择离子监测模式,外标法定量。结果：在0.02-10 mg/kg的范围内线性良好（r＆gt;0.99）,在0.25-1.00 mg/kg的添加水平范围内,平均回收率为93%-107%,相对标准偏差（RSD）为5.2%-9.2%,检出限（LOD）为0.02 mg/kg。结论：该方法简便、快速、灵敏、准确、低成本、耐用,适合乳粉中三聚氰胺确证和定量测定。

Objective： To establish gas chromatography-mass spectrometric method for the quantitative determination and confirmation of melamine in milk powder.Methods：Milk powder was extracted with acetic acid-acetonitrile water solution.An aliquot of the filtrate was cleaned up using mixed-mode cation exchange solid-phase extraction cartidges,evaporated to dryness under notrogen gas and the residue was converted to trimethylsilyl derivatives which was determined by gas chromatography-mass spectrometry in selected ion monitoring（SIM） mode and external standards were used for quantitative determination.Results：The linear range was from 0.02 to 10 mg/kg.The average recoveries were 93%107% and relative standard deviations were 5.2%9.2% in the spiked range of 0.251.00 mg/kg.The limit of detection were 0.02 mg/kg.Conclusion：The method is simple,rapid,sensitive,accurate,cheap,and rugged.It is suitable for the quantitative determination and confirmation of melamine in milk powder.