Determination of Harmful Elements Cu, Ni, Cd and Pb in Flotation Samples of Rare and Precious Gold Mines by ICP-MS with Matrix-Matching Method

For the quantification analysis of harmful elements (such as Ni, Cu, Cd and Pb), which may be with the same grade or high content as gold elements, complex matrix of gold ore can produce inhibitory effects, weaken the ionization rate, reduce the signal response, and finally show negative effect on measurement results. In this paper, inductively coupled plasma-mass spectrometry (ICP-MS) with matrix-matching was applied. Compared with the standard solution of harmful elements with pure regent, harmful elements standard solution in complex matrix can reduce the difference in matrix with the dissolving solution of sample. The accurate determination of harmful elements can be achieved with the calibration of non mass spectrometry interference by the internal standard solution and matrix-matching. Main matrix elements of each floatation product of gold ore were determined by the mineralogical analysis, and sample dissolution was conducted by the microwave digestion with HCL-HNO₃-HF. Relative deviations of quantification results of 10 μg/L harmful elements in single and mixed matrix element solutions of 500 μg/mL and 1000 μg/mL are less than ± 10%, which indicates that the influence of high concentration matrix on quantification results of trace harmful elements is relatively small. Quantitative deviation of harmful elements in flotation samples of various matrix types were less than 20%, which was measured by harmful elements standard solution with single and two types of matrix elements of 1000μg/mL. Hence, the harmful element standard solution with the Fe-S matrix was applied for the determination of harmful elements in floatation products of gold ore. For the spiked recovery experiment of representative samples measured by the standard solution, the elemental spiked recovery rate ranged from 92.08% to 106.05%. Six parallel tests were conducted on representative samples, and the relative standard deviation (RSD) of each element was 1.21%-4.69%. Above conclusions indicate that the ICP-MS with matrix matching method is suitable for quantification determination of harmful elements in gold flotation samples.