表面解吸常压化学电离质谱法直接测定奶粉中三聚氰胺

Surface Desorption Atmospheric Pressure Chemical Ionization Mass Spectrometry for Direct Detection Melamine in Powdered Milk Products

应用表面解吸常压化学电离(SDAPCI)质谱法,在无需样品预处理的情况下,直接测定了奶粉中三聚氰胺,并用串联质谱法对测定结果进行了鉴定。采用手动进样,单个样品测定时间少于0.5 min,回收率为86.7%～112.8%;相对标准偏差(RSD)为4.3%～10.3%;对奶粉中三聚氰胺的检出限为8.8μg/kg。方法适用于批量样品的快速半定量检测。

A novel method was developed for the direct detection of trace amounts of melamine in powdered milk products by using surface desorption atmospheric pressure chemical ionization mass spectrometry（SDAPCI-MS） without any sample pretreat ment. Taking the advantage of multiple-stage tandem MS capability of an ion trap mass analyzer, all the signals detected from milk powders were quickly identified using the characteristic fragments of melamine, resulting in confident validation of the analytical results. The average time for a single sample analysis was less than 0.5 min; the speed was largely determined by the sample loading which took more than 29 s for each manual delivery. The recoveries for five samples spiked with 1 -5 mg/kg melamine were 86.7% -112.8% , and the relative standard deviations of the method were 4.3% -10.3%. The limit of determination of this method was found to be 8.8 μg/kg. The data show SDAPCI-MS is a powerful tool for rapid, semi-quantitative detection of melamine in food products.