Abstract An electrochemical separation procedure has been developed for the speciation of Cr(VI) and V(V) in water samples. The sensing technique was based on the direct linear sweep voltammetric reduction of Cr(VI) and V(V) on a multi-walled carbon nanotube-neutral red-gold nanoparticles (MWCNTs-NR-AuNPs) modified commercially available screen-printed carbon electrode (SPCE). In this study, MWCNTs attached on the surfaces of NR-AuNPs via the covalent bonding between the carboxylic acid of MWCNTs and the free amine group of neutral red. The peak to peak separation of V(V) and Cr(VI) was about 269 mV, Total chromium and vanadium were determined after oxidation of Cr (III) to Cr(VI) and V(IV) to V(V) by potassium permanganate oxidation. The linear range of Cr(VI) and V(V) was 0.4–80 µM and 3–200 µM with the detection limits of 0.025 µM and 0.42 µM (S/N = 3), respectively. The recoveries of Cr(VI), Cr(III), V(V) and V(IV) were 97–99%, 96–98%, 97–99% and 95–98%, respectively, HorRat were calculated to 0.60–0.91 for Cr(VI), 0.55–1.11 for Cr(III), 50–1.16 for V(V) and 0.63–1.23 for V(IV), respectively. The proposed electrochemical separation procedure shows appropriate sensitivity and offers an alternative to the simultaneous detection and speciation of target metal ions.

中文翻译：

---

中性红色互连金纳米粒子/多壁碳纳米管修饰的电化学传感器，用于同时检测水样中的铬 (VI) 和钒 (V)

摘要 已开发出一种电化学分离方法，用于水样中 Cr(VI) 和 V(V) 的形态分析。传感技术基于 Cr(VI) 和 V(V) 在多壁碳纳米管中性红金纳米粒子 (MWCNTs-NR-AuNPs) 上的直接线性扫描伏安法还原，改进的市售丝网印刷碳电极(SPCE)。在这项研究中，多壁碳纳米管通过多壁碳纳米管的羧酸与中性红的游离胺基团之间的共价键附着在 NR-AuNPs 的表面上。V(V) 和 Cr(VI) 的峰间分离度约为 269 mV，总铬和钒在 Cr (III) 被钾氧化成 Cr(VI) 和 V(IV) 成 V(V) 后测定高锰酸盐氧化。Cr(VI) 和 V(V) 的线性范围为 0.4–80 µM 和 3–200 µM，检测限为 0.025 µM 和 0。分别为 42 µM (S/N = 3)。Cr(VI)、Cr(III)、V(V) 和 V(IV) 的回收率分别为 97–99%、96–98%、97–99% 和 95–98%，计算得出 HorRat 为 0.60 Cr(VI) 为 –0.91，Cr(III) 为 0.55–1.11，V(V) 为 50–1.16，V(IV) 为 0.63–1.23。所提出的电化学分离程序显示出适当的灵敏度，并为目标金属离子的同时检测和形态形成提供了替代方案。