TRACE-ELEMENT ANALYSIS OF GEOLOGICAL SURVEY OF JAPAN SILICATE REFERENCE MATERIALS - COMPARISON OF SSMS WITH ICP-MS DATA AND A CRITICAL DISCUSSION OF COMPILED VALUES

The concentrations of 29 trace elements have precisely been determined in 15 international silicate reference materials of the Geological Survey of Japan by spark source mass spectrometry (SSMS) and inductively coupled plasma-mass spectrometry (ICP-MS). The samples span a wide range of concentration levels. Most of the SSMS and ICP-MS values agree within analytical error down to the ppb concentration range. Of particular interest are the data for Nb, Y, Zr, Th, U in samples with low trace element concentrations (< 1-10 ppm), for which published data are quite variable. The results obtained generally agree with those of modern sensitive analytical techniques (such as ICP-MS, HPLC), but are often much lower than standard XRF and compiled reference values. It is suggested that these discrepancies arise from calibration and analytical problems for standard XRF and ICP-MS and incorporation of these data into compiled values. More judicious selection of data based on analytical methodology and geochemical behaviour is required for samples which challenge the detection limits of standard analysis.