不同消化方法-电感耦合等离子体质谱法测定红茶中15种金属元素的比较

ICP-MS Determinations on Metals in Black Tea Pretreated by Different Digestion Methods

本试验分别采用干法灰化法、湿法消解法、微波消解法3种不同的消化方法作为前处理方式,用电感耦合等离子体质谱法(ICP-MS)测定红茶中15种金属元素。试验结果表明:干法灰化法处理测定的金属元素含量高于湿法消解法,而微波消解法处理测定的含量高于干法消解法。采用内标法,对各个元素的检出限、线性范围、3种前处理基本参数进行了研究,并进行了标准物质测定和精密度试验。选用微波消解法处理样品,标准物质测定值更接近标准参考值,相对标准偏差<2%,干灰化法优于湿法消解法,相对标准偏差分别为2%~3%、3%~5%。微波消解前处理方式明显优于其他两种前处理方法,简便、快速、准确率高,适用于多种金属元素的同时测定。

Using ashing,wet or microwave method to pretreat samples for the inductively coupled plasma mass spectrometry(ICP-MS)in determining 15 metal elements in black tea was conducted to compare their applicability.The microwave digestion yielded measurements on the metals higher than the ashing or the wet digestion.Following a pretreatment,the detection limits and linear range of ICP-MS on each metal element with internal standards were determined.On the pretreatment methods,3 parameters were applied for comparison.The precision test for the methodology was conducted with reference standards.The microwave digestion delivered results with a relative standard deviation less than 2%against the standards,while those of the ashing method 2%~3%and the wet digestion 3%~5%.Thus,the sample digestion by microwave was considered superior to the other two methods for determinations of 15 metals in the tea.