Determination of Au and Ag in Geological Samples by Loaded Polyurethane Foam-Inductively Coupled Plasma-Mass Spectrometry / 分析化学

ABSTRACT

The relatively high abundance of geochemical elements such as Nb, Zr, Y and other elements shows serious interferences in the determination of trace silver in geochemical samples by inductively coupled plasma-mass spectrometry ( ICP-MS) . Thus it will lead to large deviation in the determination of geochemical samples without separation and enrichment. The traditional emission spectrum or graphite furnace atomic absorption method is only single-element analysis to the silver and with bad sample representativeness. In this study, load diphenylthiourea ( DPTU) foam selective enrichment was used for the separation of Au and Ag from other interfering elements in geological samples, and thiourea liberation-ICP-MS method was developed for the simultaneous determination of Au and Ag. The samples were first decomposed by 11 aqua regia. After addition of 50 mL of water, the samples were adsorbed under oscillation for 30 min at 20℃. The detection limits of the Au and Ag were 0. 02 ng/g and 0. 007μg/g, respectively. The proposed method was successfully applied to the determination of Au and Ag in eight national standard materials.