Determination of Trace Elements in High Purity Silver Granules Using Sector Field Inductively Coupled Plasma Mass Spectrometry

Abstract

Abstract The trace impurities in high-purity silver granules were determined by fast scanning single collector sector field high-resolution inductively coupled plasma mass spectrometry (HR-ICPMS) after selective separation of the major matrix and silver as silver metal by hydroxylamine hydrochloride. In the filtrate, 32 major and minor metallic impurities including silver were determined using NIST SRM 1643e, Trace Elements in Water, VHG SM75 and SM90 (VHC Labs, Inc., Manchester, NH), and internal standards 7Li, 9Be, 45Sc, 72Ge, 115ln, 209Bi, and 238U. To minimize the matrix effect, reagent blank was measured and subtracted from the samples. The spectral interferences have been resolved by measuring the isotopes 55Mn, 56Fe, 75As, and 78Se in high-resolution mode (m/Δm = 10,000); 52Cr, 63Cu, and 64Zn in medium-resolution mode (m/Δm = 4,000); and others in low-resolution mode (m/Δm = 300). In the present study, the purity of the tested silver granules was found to be 99.9898 ± 0.00007 % with 95 % confidence level. The purity results obtained from impurity assessment by HR-ICPMS were compared with those of the results of the conventional gravimetric method and found to be comparable. Though the gravimetric process is a primary technique for purity determination and the results obtained are directly traceable to SI units, HR-ICPMS provides more information about the impurities present in the silver granules. The proposed method is convenient, accurate, and precise and can be used for purity as well as for determination of trace impurities in silver metal.