Precise Determination of Cadmium, Indium and Tellurium Using Multiple Collector ICP‐MS

Abstract

New sample preparation and ion‐exchange separation methods as well as instrumental measurement protocols were established for the determination of trace‐level Cd, In, and Te concentrations in geological materials by isotope‐dilution mass spectrometry. High precision isotope ratio measurements were performed with a multiple collector inductively coupled plasma‐mass spectrometer (MC‐ICP‐MS). The mass biases incurred for In and Te were corrected by adding and monitoring Pd and Sb standard solutions, respectively. Mass fractionation of Cd was corrected by using the mass fractionation factor calculated from the measurement of a standard solution. The measurement precision was better than 1 % for Cd, In and Te. Detection limits were < 1 ng g ‐1 for Cd, < 0.02 ng g ‐1 for In and Te. Using these new analytical techniques, the concentrations of Cd, In and Te were determined in six international geological reference materials. Concentrations could be reproduced within 3% for Cd, 4% for In and 10% for Te. Sample heterogeneity and volatility problems might have been the reason for the relatively large differences between Te replicates. Our results displayed excellent reproducibility compared with those of other techniques and agree well with data from previously published recommended values.