Faculty of Chemistry and Pharmacy, University of Sofia "St. Kliment Ohridski", 1, J. Bourchier Blvd., 1164 Sofia, Bulgaria.
Department of Chemistry, University of Mining and Geology "St. Ivan Rilski", Students Town, "Prof. Boyan Kamenov" Street, 1700 Sofia, Bulgaria.
Molecules. 2021 Sep 6;26(17):5418. doi: 10.3390/molecules26175418.
In this study, a new method for selective determination of Cr(VI) in water samples at pH 4 is presented using raffinose capped silver nanoparticles (Ag/Raff NPs) as an optical sensor. The method is based on the variation of LSPR absorption band intensity as a result of electrostatic interaction between the negatively charged Ag/Raff NPs and positive Cr(III) ions, in-situ produced by chemical reduction of Cr(VI) with ascorbic acid, combined with the fast kinetics of Cr(III) coordination to the -OH groups of the capping agent on the nanoparticle surface, further causing the nanoparticle aggregation. The calibration curve for Cr(VI) is linear in the range 2.5-7.5 μmol L, the limit of quantification achieved is 1.9 μmol L, and values of relative standard deviation vary from 3 to 5% for concentration level 1.9-7.5 μmol L. The interference studies performed in the presence of various metal ions show very good selectivity of Ag/Raff NPs toward Cr(VI) species. The added-found method is used to confirm the accuracy and precision of developed analytical approach.
在这项研究中，提出了一种新的方法，用于在 pH 值为 4 的水样中选择性测定六价铬（Cr(VI)），使用棉子糖封端的银纳米粒子（Ag/Raff NPs）作为光学传感器。该方法基于 LSPR 吸收带强度的变化，这是由于带负电荷的 Ag/Raff NPs 与通过抗坏血酸化学还原原位产生的正三价铬（Cr(III)）离子之间的静电相互作用，与在纳米粒子表面的封端剂的-OH 基团快速配位的 Cr(III)相结合，进一步导致纳米粒子聚集。Cr(VI)的校准曲线在 2.5-7.5 μmol L 的范围内呈线性，实现的定量限为 1.9 μmol L，浓度水平为 1.9-7.5 μmol L 时，相对标准偏差值从 3%变化到 5%。在存在各种金属离子的情况下进行的干扰研究表明，Ag/Raff NPs 对六价铬（Cr(VI)）具有很好的选择性。加标法用于确认所开发分析方法的准确性和精密度。
