Determination of trace impurities in high purity gallium by inductively coupled plasma mass spectrometry and cross validation of results by transverse heated graphite furnace atomic absorption spectrometry

Abstract

Trace impurities in gallium samples were determined by inductively coupled plasma mass spectrometry (ICP-MS) after enrichment of trace impurities, nobler than Ga (Ag, Bi, Co, Cu, Fe, Ni, and Pb) on residual gallium in a mixture of HCl and HNO 3 (Jackwerths' procedure). The elements leached into the solution (Al, Cd, and Mn) were determined by removing the matrix from the solution after HCl-MIBK extraction. Direct determination after dissolution of gallium in nitric acid was also attempted. Interferences encountered in the determination are discussed. The results obtained have been cross validated with transverse heated graphite furnace atomic absorption spectrometry (THGFAAS) and the correlation coefficient R was found to be 0.995. Limit of detection in mg/kg obtained by ICP-MS were 0.0003 for Ag; 0.008 for Bi; 0.008 for Cu; 0.007 for Ni; 0.003 for Pb and by THGFAAS were 0.0014 for Ag; 0.075 for Bi; 0.005 for Cu; 0.003 for Ni and 0.004 for Pb after partial dissolution taking 2.0 g of the sample. For Co the limit of detection by both the techniques was 0.003 mg/kg while 0.003 mg/kg was obtained for Fe using THGFAAS.