Determination Of Sb Isotope Ratios In Stibnite Using Fs-LA-MC-ICP-MS And Two Potential Reference Materials Study

Abstract

: This study demonstrates an analytical method for the high spatial resolution (20 µm) and high-precision determination of antimony (Sb) isotope composition in stibnite, using femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry (fs-LA-MC-ICP-MS). The potential matrix effect-inducing elements in Sb isotope composition measurements exhibit extremely low concentrations in two newly introduced natural stibnite reference materials, DC and BJS, rendering their impact virtually negligible during fs-LA-MC-ICP-MS analysis. Through reciprocal correction of DC and BJS, consistent results were achieved, aligning with those obtained by SN-MC-ICP-MS, indicating an absence of discernible matrix effects between the two samples. A comprehensive assessment was conducted to evaluate the contribution of the Sn standard solution to enhance the external precision of measurements. The 2SD of δ 123 Sb mean values increased by 0.02‰ to 0.04‰. Adjusting the laser ablation spot size (5μm-80μm) to control signal intensity, we investigated the deviation in δ 123 Sb caused by mismatched signal intensities between the sample and the reference material. The matching range of signal intensity between the reference sample and the test sample was within -40% to 140%, ensuring satisfactory precision. Additionally, once the signal intensity of 121 Sb exceeded 15V, the internal precision of the 123 Sb/ 121 Sb ratio no longer exhibited a significant decline. Measurements of DC and BJS were conducted using fs-LA-MC-ICP-MS, coupled with SN-MC-ICP-MS, backscattered electron maps (BSE) and elemental compositions, confirming the accuracy of this method and the homogeneity of the two potential reference materials.