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 Su rvey of Japan by spark source mass spectrometry (SSMS) and inductively coupled plasma-mass spectrometry (ICP-MS). The samples span a wide ra nge of concentration levels. Most of the SSMS and ICP-MS values agree within analytical error down to the ppb concentration range. Of partic ular interest are the data for Nb, Y, Zr, Th, U in samples with low tr ace element concentrations (< 1-10 ppm), for which published data are quite variable. The results obtained generally agree with those of mod ern sensitive analytical techniques (such as ICP-MS, HPLC), but are of ten much lower than standard XRF and compiled reference values. It is suggested that these discrepancies arise from calibration and analytic al problems for standard XRF and ICP-MS and incorporation of these dat a into compiled values. More judicious selection of data based on anal ytical methodology and geochemical behaviour is required for samples w hich challenge the detection limits of standard analysis.