微波消解-ICP-AES/ICP-MS测定大米中微量元素

Determination of trace elements in rice from different regions with microwave digestion and ICP-AES/MS

采用微波消解技术,电感耦合等离子体光谱(ICP-AES)和电感耦合等离子体质谱(ICP-MS)测定了分别产自辽宁、四川、湖南三地的大米中21种元素B、Ba、Ca、Cd、Cu、Fe、K、Mg、Mn、Na、P、S、Sr、Zn、Co、Ni、Cr、Mo、Pb、Li、Cs。所有元素标准曲线回归方程线形系数均大于0.999,各元素相对标准偏差(RSD)均小于5.31%(测定次数n=4),加标回收率为96.6%～110.6%,方法检出限:ICP-AES为0.0048～0.33μg·mL-1,ICP-MS为0.022～0.192ng·mL-1。用国家一级标准物质大米(GBW10010)验证了方法的准确性,测定值与推荐值相符,实验表明,P、S、K、Mg、Ca、Na、Zn、Mn、Fe、Cu在大米中含量较高。此方法简便、快速,适用于大米等粮食作物中微量元素的测定。

After microwave digestion, three rice samples from Liaoning, Sichuan and Hunan were respectively determined by inductively coupled plasma atomic emission spectrometry （ICP-AES） and inductively coupled plasma mass spectrometry （ICP-MS）. Twenty one elements including B, Ba, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, P, S, Sr, Zn, Co, Ni, Cr, Mo, Pb, Li and Cs in rice samples were studied. The linear correlation coefficient （r） of each linear regression equation for the corresponding element is over 0.999, and each relative standard deviation （n=4） is under 5.31%. The recoveries of the method are in the range of 96.6%-110.6%. The detection limit of ICP-AES is in the range of 0.0048-0.33 μg·mL-1, and that of ICP-MS is in the range of 0.022-0.192ng·mL-1, for all elements. The proposed method is validated by the analyses of the rice national standard materials （GBW10010）, and the results agreed with the certified values. The experiment results show that the concentrations of P, S, K, Mg, Ca, Na, Zn, Mn, Fe and Cu are relatively high in the rice. The proposed method is rapid and convenient, and it is suitable for the determination of trace elements in food, such as rice.