Determination of chalcophile elements in sulfide-bearing rocks by hydride generation inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass spectrometry

Abstract

Inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry with the preliminary hydride generation (HG-ICP-OES) techniques were used for the determination of chalcophile elements in sulfide-bearing rocks after different sample pretreatment. As and Se in the hydrochloric acid leaching solutions could not be determined neither by quadruple MS with correction equations, no by high resolution (HR-MS) (R = 10,000) due to high СHCl/СAs,Se ratio. Se, Sn, Ga, Bi, Te, Sb, Ge, Cd, Tl and Pb in hydrochloric acid leaching solutions can be determined by ICP-MS, and As, Se, Sn, Bi, Te and Sb by HG-ICP-OES. Main matrix elements - Co, Ni, Fe, Cu – don't affect the signal of analytes in case of ICP-MS method. The matrices of the sulfide ores and rocks were shown to significantly suppress the signals of the all elements using HG-ICP-OES techniques. To eliminate the influence of matrix components, the use of auxiliary reagents – 5% (m/V) KI and 0.5% (m/V) ascorbic acid C6H8O6 as well as 5% (m/V) KBr – has been proposed. Optimal conditions for obtaining the hydrides and for the determination of hydride-forming elements by HG-ICP-OES were established. Addition of KI and ascorbic acid mixture allows the determination of As, Sn, Bi and Sb. Six elements - Se, Te, As, Sn, Bi and Sb could be determined in the presence of 5% (m/V) KBr.The Сmin values for the determination of these elements by ICP-MS and HG-ICP-OES methods are comparable and vary between 0.01 and 0.02 μg g−1 for As, Se, Sb and Bi, and between 0.05 and 0.1 μg g−1 for Sn and Te.