微波消解/ICP-MS法测定烟草中微量元素含量

采用2 mL 50% HNO₃和1 mL 47% H₂O₂作为消解体系,最终消解液酸度在2%左右对烟草样品进行微波消解,标准溶液采用2% HNO₃稀释,添加Ge和Rh内标元素,直接进行ICP-MS分析。此方案避免采用浓酸,可省去赶酸或稀释的繁琐步骤,延长仪器相关部件使用寿命,消除由于样品溶液与标准溶液酸度差别较大带来的误差。测试考察了烟草中30种微量元素,给出7个烟草产区样品中8种微量元素的测定结果。方法检出限为0.006～1.133 ng·mL-1,相对标准偏差0.90%～5.66%,Cu和Y回收率93%～102%。结果表明,文章所提出的微波消解方法适用于烟草中多种微量元素的同时测定,烟草样品微量元素含量与烟草产地、类别有紧密联系。

Determination of Trace Elements in Tobaccos by Microwave Digestion/ICP-MS Method

2 mL 50% HNO₃ and 1 mL 47% H₂O₂ were chosen for tobaccos digestion, and the acidity of final digestion solution was confined to about 2%. Standard solutions were diluted with 2% HNO₃. The digestion solutions were determined by ICP-MS directly after adding internal standard elements Ge and Rh. In stead of using concentrated acid, this method not only can leave out the process of drying or dilution and extended the life of relevant components of the instrument, but also eliminate the errors of the inconsistency between digestion solutions and standard solutions could be eliminated. The contents of 30 trace elements, the results of eight representatives of which were provided, in tobaccos from seven areas were determined. The detection limits of measured elements were from 0.006 to 1.133 ng·mL-1. The relative standard deviations were from 0.90% to 5.66%. The recovery rates of two elements (Cu, Y) were from 93% to 102%. The results showed that this method proposed could be applied to multielement simultaneous determination of tobaccos, and there is a deep relationship between the contents of the trace elements and the production place and classification of tobaccos.