A simple method for the precise determination of multi-elements in pyrite and magnetite by ICP-MS and ICP-OES with matrix removal

Abstract

A simple, economical, and rapid chemical method was developed for the precise measurement of major and trace elements in bulk pyrite and magnetite. This method, which required only 10–20 mg of sample, used inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES) with a polyurethane foam (PUF)-based matrix removal step. Interference derived from the iron-rich mineral matrix was reduced by the removal of iron from the sample solution using 0.18 g PUF in 6 M HCl. The extraction conditions (e.g., temperature, shaking time, and initial iron concentration) were intensively investigated to achieve high iron separation efficiency. An iron removal rate of 92.7 ± 0.7% (n = 3, SD) and recoveries of 97–103% for 17 trace elements were obtained under the optimized separation conditions. To evaluate the feasibility of our method, reference materials for pyrite (GBW07267) and iron formation (FER-1 and FER-2) were analyzed. Our results were consistent with the certified values or literature values, and the precision was comparable to the certified uncertainty or that of previous methods in which 100 mg of sample powder was digested. These results confirmed that this novel method is an efficient technique for the precise measurement of multi-elements in pyrite and magnetite. Relative to other methods, our protocol has great potential for analyzing a wide variety of trace elements in small amounts (<10 mg) of iron-rich samples with applicability in geochemistry, cosmochemistry, and environmental studies.