Published online by Cambridge University Press: 06 March 2019
Brieketted rock powder discs provide a convenient type of specimen for use in x-ray fluorescent analysis for both major and trace elements. The method is limited because variation of matrix makes calibration difficult over more than a limited range of specimen compositions.
Standard grinding and preparation procedures together with a ratio technique of measurement eliminate variation except that arising from chemical, mineralogical and particle size differences. Several series of standard rock samples have been prepared and the variation of measured intensity per unit concentration have been investigated for the analytical Lines of silicon, aluminium, iron, selenium and cadmium. Computer methods of multivatiate regression analysis have been used to calculate empirical correction factors based on this data and the mineralogical and chemical composition of the specimens. These correction factors have been used to correct the measured intensities of other specimens measured in separate experiments.