电感耦合等离子体质谱法测定稀土系贮氢合金中镉和铅

摘要

采用硝酸低温溶解试样,以2%(V/V)硝酸为测定介质,建立了电感耦合等离子体质谱法(ICP-MS)测定稀土系贮氢合金中镉和铅的方法.以111Cd和208Pb作为测定同位素,消除了同量异位素和多原子离子的质谱干扰;以10.0 ng/mL的133Cs为内标校正了基体效应和仪器信号漂移.镉和铅元素的校准曲线相关系数均大于0.999 8,线性关系良好,方法检出限分别为0.03 ng/mL和0.04 ng/mL,方法测定下限分别为0.10 ng/mL和0.13 ng/mL.采用在稀土系贮氢合金试样中加入镉和铅标准溶液的方法配制稀土系贮氢合金合成试样,按实验方法进行处理并测定,测得结果与电感耦合等离子体原子发射光谱法(ICP-AES)测定结果基本一致.采用实验方法对稀土系贮氢合金中铅进行测定,相对标准偏差(n=11)为4.2%,镉和铅的加标回收率分别为96%~104%和95%~102%.%Afer the sample was dissolved with nitric acid at low temperature, a determination method of cadmium and lead in rare earth based hydrogen storage alloy was established by inductively coupled plasma mass spectrometry (ICP-MS) with 2% (V/V) nitric acid as determination medium.111Cd and 208Pb were selected as determination isotopes to eliminate the mass spectrometry interference of isobars and polyatomic ions.The matrix effect and instrumental signal drift were corrected with 10.0 ng/mL 133Cs as internal standard.The correlation coefficients of calibration curves for cadmium and lead were higher than 0.999 8, indicating the good linear relationship.The detection limit of method was 0.03 ng/mL and 0.04 ng/mL, respectively.While the lower limit of determination was 0.10 ng/mL and 0.13 ng/mL, respectively.The synthetic samples of rare earth based hydrogen storage alloy were prepared by adding standard solution of cadmium and lead into rare earth based hydrogen storage alloy samples, and then treated and determined according to the experimental method.The results were consistent with those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES).The proposed method was applied for the determination of lead in rare earth based hydrogen storage alloy.The relative standard deviation (RSD, n=11) was 4.2%.The recoveries for cadmium and lead were 96%-104% and 95%-102%, respectively.