Insights into the inter-element effects in the EDXRF determination of zirconium in binary aqueous solutions via the calibration method

Abstract

Calibration of the energy dispersive X-ray fluorescence (EDXRF) spectrometer, using pure elemental standard solutions of Cu, Zr, Nb, Mo, Ta, and U, was carried out and the instrumental sensitivity was derived for each. The effects of the presence of the rest of these elements on the calibration of Zr were evaluated by analyzing the respective binary solutions, separately. All the matrix elements led to a reduction in the Zr- sensitivity of the spectrometer. Intercepts of the calibration curves were found to decrease with Cu, Mo. Nb, Ta, and U led to the elevation of the intercepts. The highest specific changes (per mg of the matrix) in both the slope and intercept were observed upon the addition of Mo. Numerically, these values were -5,917 and -1,187 respectively. Limits of detection for Zr, from the calibration curve, were the best (0.28 μg) in the presence of 7.8 mg Mo and the worst (165.4 μg) in the presence of 53 mg U. The results were validated by multiple standard additions on a sample and analysis of reference standard solution of Zr. Quality control sample analysis re-affirmed the accuracy of the present results. Repeatability was also established for the measurements of solution samples.