Rusiniak Piotr, Wątor Katarzyna, Kmiecik Ewa, Vakanjac Vesna Ristić
AGH University of Krakow, Mickiewicza 30 Av., 30-059, Krakow, Poland.
Faculty of Mining and Geology, University of Belgrade, Đušina 7, Beograd, Serbia.
Sci Rep. 2024 Dec 16;14(1):30502. doi: 10.1038/s41598-024-77425-3.
The study focuses on validating reference methods such as ICP-OES and ICP-MS for detecting ultra-trace levels of chromium in groundwater, where concentrations are typically very low. Additionally, it verifies a hyphenated technique, IC-ICP-MS, for determining naturally occurring Cr(VI) in tested waters. The validation process involved various chromium analysis variants, including isotopes Cr and Cr in ICP-MS and IC-ICP-MS techniques, along with specific emission lines in the ICP-OES technique. Statistical data processing revealed that the achieved limits of quantification for Cr in different techniques ranged from 0.053 µg/L to 1.3 µg/L, with the associated measurement uncertainty estimated between 14% and 19% (at a coverage factor k = 2, 95%). For speciation analysis, it was possible to quantitatively determine Cr(VI) at concentrations as low as 0.12 µg/L, with the measurement uncertainty ranging between 10% and 14%. The Kruskal-Wallis test indicated that for the 14 water samples analysed, there was no statistically significant difference in the results obtained using different analytical techniques (p > 0.05). The geochemical modelling approach applied enhances the understanding of chromium speciation in water samples, verifying the accuracy of speciation analysis and identifying specific ion forms in which Cr(III) and Cr(VI) occur. In the analysed water samples, the concentration of Cr(VI) ranges between 0.13 and 35 µg/L, with the primary form identified as the oxoanion CrO. Importantly, statistical tests demonstrated no statistically significant differences between the total chromium concentration in water and the concentration of Cr(VI), indicating that the entire concentration of total chromium corresponds to Cr(VI) speciation.
该研究聚焦于验证诸如电感耦合等离子体发射光谱法（ICP - OES）和电感耦合等离子体质谱法（ICP - MS）等参考方法，用于检测地下水中超痕量水平的铬，因为地下水中铬的浓度通常非常低。此外，还验证了一种联用技术——离子色谱 - 电感耦合等离子体质谱法（IC - ICP - MS），用于测定受试水体中天然存在的六价铬（Cr(VI)）。验证过程涉及多种铬分析变体，包括ICP - MS和IC - ICP - MS技术中的铬同位素Cr和Cr，以及ICP - OES技术中的特定发射线。统计数据处理表明，不同技术中铬的定量限达到0.053微克/升至1.3微克/升，相关测量不确定度估计在14%至19%之间（覆盖因子k = 2，95%）。对于形态分析，能够定量测定低至0.12微克/升浓度的Cr(VI)，测量不确定度在10%至14%之间。克鲁斯卡尔 - 沃利斯检验表明，对于分析的14个水样，使用不同分析技术获得的结果在统计学上没有显著差异（p > 0.05）。所应用的地球化学建模方法增强了对水样中铬形态的理解，验证了形态分析的准确性，并确定了Cr(III)和Cr(VI)存在的特定离子形式。在分析的水样中，Cr(VI)的浓度范围在0.13至35微克/升之间，主要形式被确定为含氧阴离子CrO。重要的是，统计检验表明水中总铬浓度与Cr(VI)浓度之间没有统计学上的显著差异，这表明总铬的整个浓度对应于Cr(VI)形态。
