基于ICP-MS/MS技术测定大米中30种微量元素

选用5种大米样品,经微波消解后应用电感耦合等离子体串联质谱（ICP-MS/MS）技术进样分析，建立测定大米中30种常见微量元素的方法。在MS/MS模式下，采用 H₂、O₂ 、NH₃为反应气，使干扰物或分析物与反应气发生质量转移反应，利用原位质量法或质量转移法消除质谱干扰。结果表明每种元素在选用合适的反应气下各待测元素线性关系良好，线性相关系数≥0.9991。30种元素的检出限为0.000251～2.322 mg/kg，加标回收率在95.50%～104.35%之间，相对标准偏差RSD≤4.03%。采用所建立的方法分别测定来自国内不同地区的大米，结果显示:5种大米中P、S、K、Mg的含量较高，在53.7~736 mg/kg之间，而重金属元素Cr、As、Cd、Pb的含量低于国家标准限量。该方法具有样品前处理简单、灵敏度高、检出限低等特点，能准确监控大米中微量元素。

Determination of 30 Trace Elements in Rice Based on ICP-MS/MS

In 5 kinds of rice samples, the method for determining 30 common trace elements in rice was established. The rice sample was digested by microwave and then injected for analysis by inductively coupled plasma tandem mass spectrometry(ICP-MS/MS) technology. In MS/MS mode, H₂, O₂, and NH₃ were used as the reagent gas to cause the interference or analytes to undergo a mass transfer reaction with the reagent gas, using in-situ mass method or mass transfer method to eliminate mass spectrum interference. The results showed that the linear relationship of the test elements was good, and the linear correlation coefficient was more than 0.9991. The limits of detection were in the range of 0.000251～2.322 mg/kg. Recoveries of the method were in range of 95.50%～104.35%, and the relative standard deviations RSD was less than 4.03%. The established method was used to determine the rice from different regions in China. The results showed that the content of P, S, K, and Mg in the five kinds of rice was higher,between 53.7~736 mg/kg, while the content of heavy metal elements Cr, As, Cd, and Pb was very low. This method has the characteristics of simple sample preparation, high sensitivity and low detection limit, and can accurately monitor the trace elements in rice.