用电感耦合等离子体质谱法(ICP-MS)法直接测定铅栅板中钙、锡、铝、锑、银、铋、铁、锌、镍、镉、铜、砷等12种元素含量.样品用硝酸(1+2)溶解后,用硫酸作沉淀剂,95%-98%的铅以生成PbSO4的形式沉淀,降低了测量过程中的铅离子强度,得到了较低的检出限.加入适量的盐酸,有效地防止了锡、锑等元素的水解.选择适当的同位素,克服了测定过程中的质谱干扰,以元素45Sc、115In、204Tl作内标,采用内标法有效地补偿了因基体效应、接口效应及仪器波动的影响.方法的加标回收率为93.2%-105.0%,相对标准偏差为2.0%-7.0%.

Simultaneous determination of 12 impurity-elements in lead grid (i.e.Ca,Sn,Al,Sb,Ag,Bi,Fe,Zn,Ni,Cd,Cu,As) of micro and trace quantities were effected by using ICP-MS.The sample was dissolved in HNO3 (1+2),and about 95%-98% of its lead content were removed by precipitation as lead sulfate.About 10 mL of HCl(1+99) was added to the filtrate to prevent the hydrolysis of tin(Ⅳ) and antimony (Ⅲ).The removal of majority of the matrix lead ion resulted lowering of matrix ion strength and making it favorable in the course of MS measurements and to obtain low detection limits for the elements determined.Besides the optimization of operation parameters of the instrument,selection of proper isotopes of the elements to be determined made it possible to overcome the mass spectrometric peak interferences to a great extent.The use of 45Sc,115In,and 204Tl as internal standards,the influences due to matrix effect,interface effect and fluctuation of the instrument were compensated effcctively.Recoveries obtained by standard addition method were in the range from 93.2% to 105.0% and RSD′s calculated from the results of determination were in the range of 2.0%-7.0%.