Empirical coefficient LA-ICP-MS and XRF for the determination of trace Zr, Hf, Nb, and Ta in geochemical samples

Zr, Hf, Nb, and Ta are strategic mineral elements, and their accurate determination is essential for resource exploration and geoscientific research. Due to their refractory and easily hydrolyzed nature, traditional analytical methods face challenges, such as cumbersome procedures and low efficiency. This study proposes a novel analytical technique that combines XRF and LA-ICP-MS to accurately determine Zr, Hf, Nb, and Ta in geochemical samples using a solid-solid analysis strategy. Li 2 B 4 O 7 -LiBO 2 (67:33) reagents were used to fuse geochemical reference materials and actual samples into homogeneous glass sheets at 1100 °C. The empirical coefficient method-XRF was applied to determine Zr content in the glass sheets of actual samples, providing an internal standard reference for subsequent LA-ICP-MS analysis. Given the similar chemical properties, 90 Zr was used as the internal standard for 178 Hf, 93 Nb, and 181 Ta. After measuring the mass spectral intensities by LA-ICP-MS, the calibration curves of Hf, Nb, and Ta were fitted by the empirical coefficient method, and the correlation coefficients were obtained as 0.9962 ∼ 0.9977, enabling accurate determination of these elements in actual geochemical samples. The analytical results for other geochemical reference materials showed excellent agreement with reference values, confirming the reliability of the method. The combined XRF and LA-ICP-MS approach established in this study provides an efficient, accurate, and environmentally friendly analytical pathway for determining Zr, Hf, Nb, and Ta in geochemical samples, making it particularly suitable for large-scale geochemical surveys and strategic mineral resources.