Simultaneous Quantification of V, Cr, Mn, Fe, Ni, Cu, Zn and Pb in Compound Fertilizers by Total Reflection X-ray Fluorescence Spectrometry

In this work, gallium was used as an internal standard and V, Cr, Mn, Fe, Ni, Cu, Zn, Pb in compound fertilizers were simultaneously determined by Total Reflection X-ray Fluorescence Spectrometry (TXRF) after microwave digestion with nitric acid. The detection limits of this method range from 1.0 μg/g for Pb to 7.0 μg/g for V. The RSD of all elements were less than 10%, except for Pb, which was 16%. The recoveries were 80%-120%. The lower recovery of Pb was caused by the interference of the As Kα spectral line with the Pb Lα spectral line. The results were compared with Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) and there were no statistically significant differences between the two measurements, within a confidence range of 95%. The RSD obtained by TXRF was less than that by ICP-AES for high contents of metallic elements samples. The results for different compound fertilizers show that the TXRF technique is accurate and applicable in the determination of variously metallic elements. It is inexpensive to use and maintain the TXRF. The established method is rapid and accurate.