The determination of trace amounts of platinum in glass by colorimetry, spark-source mass spectrography and X-ray fluorescence spectrometry

Abstract

Methods for the determination of less than 1 µg g^–1 of platinum in glass have been investigated and evaluated. The p-nitrosodimethylaniline colorimetric method has been adapted to enable 0·2 µg g^–1 of platinum to be determined on 2 g of sample, while the tin(II) chloride colorimetric method has been shown to be too insensitive to permit the determination of such low concentrations. Spark-source mass spectrography, while confirming the heterogeneous distribution of the platinum throughout the glass, has also been shown to be too insensitive for the direct determination of platinum in this matrix. An X-ray fluorescence procedure has been successfully developed to enable 0·5 µg of platinum in a 1-g sample of glass to be determined with a relative standard deviation of 10 per cent. The time required for the complete analysis is 3 to 4 hours. The proposed methods depend on the pre-concentration of platinum by co-precipitation with tellurium.