Direct analysis of melamine in complex matrices using a handheld mass spectrometer
Direct analysis of melamine in complex matrices using a handheld mass spectrometer
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DOI：
10.1039/b923427f
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发表时间：
2010-01-01
期刊：
影响因子：
4.2
通讯作者：
Cooks, R. Graham
中科院分区：
文献类型：
--
作者：
Huang, Guangming;Xu, Wei;Cooks, R. Graham
低温等离子体环境电离源，耦合到便携式质谱仪（Mini 10.5），用于测定全脂牛奶和相关材料中的三聚氰胺污染。用等离子体探针实现了分析物的热辅助解吸和电离。小尺寸、低功耗和无需预处理直接进样的能力使得等离子体电离成为与手持式质谱仪一起使用的合适的电离方法。用于将大气压离子源连接到质谱仪的标准不连续大气压接口（Gao等人，Anal.化学成分：2008，80，4026-4032）通过使用补充泵送来改进以增加离子转移效率。全脂牛奶，鱼，奶粉和其他复杂的基质掺入三聚氰胺被放置在靠近真空入口的载玻片上，并在没有样品预处理的情况下分析。使用质子化三聚氰胺m/z 127的MS/MS实现复杂基质中的定量，以产生m/z 85的特征碎片离子。每分钟两个样品的分析速率，全脂牛奶中三聚氰胺的水平低至250 ng/mL（低于美国1 ppm（1 μ g/mL）或欧洲2.5 ppm（μ g/mL）的监管水平），线性动态范围为0.5-50 μ g/mL，相对标准偏差约为2.5 ng/mL。达到7.6-16.2%。三聚氰胺对公众健康的重要性以及之前缺乏快速、灵敏且高度特异性的现场分析方法增加了本研究的相关性。
A low temperature plasma ambient ionization source, coupled to a portable mass spectrometer (Mini 10.5), is used for the determination of melamine contamination in whole milk and related materials. Thermally assisted desorption and ionization of the analyte was achieved with the plasma probe. The small size, low power consumption and capability for direct sampling without pretreatment makes plasma ionization an appropriate ionization method for use with a handheld mass spectrometer. The standard discontinuous atmospheric pressure interface used to connect atmospheric pressure ion sources to mass spectrometers (Gao et al., Anal. Chem., 2008, 80, 4026-4032) was modified by using supplementary pumping to increase the ion transfer efficiency. Whole milk, fish, milk powder and other complex matrices spiked with melamine were placed on glass slides close to the vacuum inlet and analyzed without sample pretreatment. Quantitation in complex matrices was achieved using MS/MS of protonated melamine m/z 127 to yield the characteristic fragment ion of m/z 85. Analysis rates of two samples per minute, levels of melamine as low as 250 ng/mL in whole milk (below the regulatory level in the US of 1 ppm (1 mu g/mL) or the European level of 2.5 ppm (mu g/mL)), a linear dynamic range of 0.5-50 mu g/mL and a relative standard deviation of ca. 7.6-16.2% were achieved. The importance of melamine to public health and the prior lack of a rapid, sensitive and yet highly specific field analysis method add to the relevance of this study.