ICP-MS DETERMINATION OF ELEMENTS OF MICRO AND TRACE AMOUNTS IN LEAD GRID

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%.