硝酸基体对ICP-MS测定香菇中镉、砷、铅的影响

Matrix Effect of Nitric Acid on the Determination of Cd,As and Pb in Mushrooms by ICP-MS

使用电感耦合等离子体质谱(ICP-MS)测试了不同硝酸浓度的标准溶液中镉、砷、铅与内标元素的CPS比值,以及测试不同赶酸时间下香菇中镉、砷、铅含量。结果表明:硝酸浓度从1%到30%,镉、砷、铅3个元素的CPS比值下降幅度分别为26.91%、28.74%、18.46%,硝酸基体效应对待测元素起了抑制作用,并且对低质量数的镉和砷的影响大于高质量数的铅;在本实验室条件下,115℃赶酸4 h的香菇中镉、砷、铅检测结果是准确的,并且赶酸2 h^6 h的,可使测定误差控制在10%以内。

Ratios of CPS of Cd,As,Pb versus internal elements with different concentrations of nitric acid were determined by inductively coupled plasma mass spectrometry（ICP-MS）. Cd,As and Pb contents of dried mushroom with different time of exhausting acid were determined. Ratios of CPS of Cd,As,Pb decreased 26.91 %,28.74 %,18.46 % when concentrations of nitric acid changed from 1 % to 30 %,respectively. Matrix effect of nitric acid depressed the signals of the determined elements. The depression degree for Pb with high mass number was greater than that for As and Cd with low mass number. The results with 4 h of exhausting acid at 115 ℃were accurate. Measurement error was less than 10 % with 2 h-6 h of exhausting acid.