A Simple Procedure for Separating Tungsten from Silicate Rocks Prior to Tungsten Isotope Ratio Determination by MC-ICP-MS

A single-column extraction chromatographic purification method for tungsten using the N-benzoyl-N-phenylhydroxylamine (BPHA) resin was investigated in this study. This method greatly simplifies the W purification procedure, and only 10 ml of acid (5 ml 3 mol l -1 HCl-0.1 mol l -1 HF and 5 ml 1 mol l -1 HF) is required to separate W from Ti, Zr, Hf, Ta and other matrix elements. The blank in the separation step was less than 0.1 ng, and the recovery of W was ~ 99%. Six independent digestion measurements of reference materials BHVO-2, BCR-2, RGM-2 and JB-2 yielded μ 182 W values (mean value with intermediate precision, 95% confidence level) of -10.3 ± 4.0 ( n = 6, 2 s )，-1.2 ± 5.3 ( n = 6, 2 s )，-1.4 ± 4.4 ( n = 6, 2 s ) and 0.6 ± 3.8 ( n = 6, 2 s ), respectively, which are in good agreement with the previously reported values.