Matrix volatilization in a flow reactor for multi-element analysis of high purity germanium by ICP-MS

Abstract

The preconcentration procedure of the trace elements for germanium analysis by mass-spectrometry with inductively coupled plasma (ICP-MS) has been developed. Trace elements were concentrated by matrix volatilization in a chlorine atmosphere. Chlorine gas is produced on site by the electrolysis of hydrochloric acid. Chlorine gas interacts with the germanium in samples during heating in the quartz cups and forms volatile germanium tetrachloride. Solid residues of trace elements concentrate were remained in the quartz cups after matrix volatilization and dissolved by mixture of nitric and hydrochloric acids for ICP-MS analysis. The behavior of analytes in the process of volatilization at different heating temperatures was studied. It is shown that the 43 elements (Ag, Al, Ba, Be, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Gd, Hf, Ho, La, Li, Lu, Mg, Mn, Na, Nb, Nd, Ni, Pb, Pd, Pr, Pt, Rb, Rh, Ru, Sc, Sm, Sr, Tb, Th, Ti, Tm, U, Yb, Zn and Zr) are quantitatively remains in the impurities concentrates. The efficiency of using of the different internal standards: 82Se, 115In, 185Re, 187Re and 209Bi for multi-element analysis by ICP-MS were studied. It is shown that preliminary matrix volatilization allows to decrease the limits of detection (LODs) of the analytes from 2.5 to 1700 times compare to conventional ICP-MS analysis. The LODs of 43 elements is in the range from 0.001 to 4 ng g−1. Accuracy of the proposed ICP-MS methods was confirmed by spike experiment and comparing with the results of independent method. This proposed matrix volatilization procedure provides to examine the high purity germanium with a total content of 43 trace elements from 0.0000014 wt%.