Department of Chemistry, National Sun Yet-sen University, Kaohsiung, Taiwan.
Analyst. 2011 Jul 7;136(13):2712-7. doi: 10.1039/c1an15162b. Epub 2011 May 18.
This study describes a simple, rapid method for sensing Cr(vi) using 5-thio-(2-nitrobenzoic acid) modified gold nanoparticles (TNBA-AuNPs) as a remover for Cr(iii) and as a sensor for Cr(vi). We discovered that TNBA-AuNPs were dispersed in the presence of Cr(vi), whereas Cr(iii) induced the aggregation of TNBA-AuNPs. Due to this phenomenon, TNBA-AuNPs can be used as a sorbent material for the removal of >90% Cr(iii), without removing Cr(vi). After centrifuging a solution containing Cr(iii), Cr(vi), and TNBA-AuNPs, Cr(iii) and Cr(vi) were separately present in the precipitate and supernatant. In other words, TNBA-AuNPs are capable of separating a mixture of Cr(iii) and Cr(vi). The addition of ascorbic acid to the supernatant resulted in a reduction of Cr(vi) to Cr(iii), driving the aggregation of TNBA-AuNPs. The selectivity of this approach is more than 1000-fold for Cr(vi) over other metal ions. The minimum detectable concentration of Cr(vi) was 1 μM using this approach. Inductively coupled plasma mass spectrometry provided an alternative for the quantification of Cr(iii) and Cr(vi) after a mixture of Cr(iii) and Cr(vi) had been separated by TNBA-AuNPs. The applicability of this approach was validated through the analysis of Cr(vi) in environmental water samples.
本研究描述了一种使用 5-巯基-(2-硝基苯甲酸)修饰的金纳米粒子（TNBA-AuNPs）作为 Cr(iii)去除剂和 Cr(vi)传感器来检测 Cr(vi)的简单、快速方法。我们发现，TNBA-AuNPs 在存在 Cr(vi)的情况下分散，而 Cr(iii)则诱导 TNBA-AuNPs 聚集。由于这种现象，TNBA-AuNPs 可用作去除 >90% Cr(iii)的吸附材料，而不会去除 Cr(vi)。在含有 Cr(iii)、Cr(vi)和 TNBA-AuNPs 的溶液离心后，Cr(iii)和 Cr(vi)分别存在于沉淀物和上清液中。换句话说，TNBA-AuNPs 能够分离 Cr(iii)和 Cr(vi)的混合物。向上清液中加入抗坏血酸会将 Cr(vi)还原为 Cr(iii)，从而导致 TNBA-AuNPs 聚集。该方法对 Cr(vi)的选择性超过其他金属离子的 1000 倍以上。使用该方法，Cr(vi)的最低检测浓度为 1 μM。电感耦合等离子体质谱法（ICP-MS）可用于在 TNBA-AuNPs 分离 Cr(iii)和 Cr(vi)混合物后定量分析 Cr(iii)和 Cr(vi)。通过分析环境水样中的 Cr(vi)验证了该方法的适用性。
