Total X-ray fluorescence analysis of geological samples using a low-dilution lithium metaborate fusion method. Matrix corrections for major elements

A low-dilution fusion method (1:2, sample to lithium metaborate) has been investigated for the determination of ten major elements in geological samples and the results are shown to have an accuracy comparable to those obtained using the well-known heavy-absorber method. Experimental determination of matrix coefficients employed natural rock standards (alone, mixed or spiked with synthetic oxides), and synthetic oxide mixtures covering a broad range of compositions of the ten most naturally-abundant oxides. The method of determining the correction coefficients is described. Flexibility of sample preparation is a feature. Experiments with varying dilution ratio (from 1:1 to 1:15, granodiorite to flux) show that the same set of correction parameters can be used throughout the range. This is practically important for samples with large ignition losses or gains and in certain other applications. Systematic differences between calculated mass absorption coefficients and the experimentally-derived correction parameters are documented and can be used in predicting parameters for additional elements. The greatest potential benefit of the low-dilution method is in automated analysis of geological and industrial samples (rocks and soils, ores and bauxites, slags, glasses, cements, refractories) for major and trace elements using only one glass disc.