Spectroscopically pure, 99.999% silicon dioxide (SiO2) from five different companies was analysed for trace element impurities by instrumental neutron activation analysis using semiconductor detectors and gamma-ray spectrometry. If large amounts of these purified SiO2 samples are added to, geological samples with low trace element contents e.g., mineral separates such as quartz, feldspar and olivine, the trace element contents of the SiO2 are a significant contaminant.
Five second generation USGS standards AGV2, BCR2, BHVO2, DTS2 and GSP2 were analyzed for trace elements by instrumental neutron activation analysis. Abundances of the rare earth elements La, Ce, Nd, Sm, Eu, Tb, Yb, Lu and eight other elements Co, Cr, Cs, Hf, Na, Sc, Ta and Th were determined in all samples, except for DTS2 which was analyzed only for Co, Cr, Na and Sc. Experimental precision and accuracy were evaluated. In general abundances of trace elements in this new generation of USGS standards are similar to the earlier standards. Abundances of Cr are, however, substantially higher in AGV2, BCR2, GSP2 and especially DTS2.