Upgrading a manual X-ray spectrograph, interfacing with an 8K computer, and employment of interelement correction programs have resulted in a several-fold increase in productivity for routine quantitative analysis and an accompanying decrease in operator bias both in measurement procedures and in calculations. Factors such as dead time and self-absorption also are now computer corrected, resulting in improved accuracy. All conditions of analysis except for the X-ray tube voltage are controlled by the computer, which enhances precision of analysis. Elemental intensities are corrected for matrix effects, and from these the percent concentrations are calculated and printed via teletype.
Interelement correction programs utilizing multiple linear regression are employed for the determination of the following minor and trace elements; K, S, Rb, Sr, Y, and Zr in silicate rocks, and Ba, As, Sb, and Zn in both silicate and carbonate rock samples. The last named elements use the same regression curves for both rock types. All these elements are determined in concentrations generally ranging from 0.0025% to 4.00%, The sensitivities obtainable range from 0.0001% for barium to 0.001% for antimony. The accuracy, as measured by the percent relative error for a variety of silicate and carbonate rocks, is on the order of 1-7%. The exception is yttrium (13.8%).