Lin Lin, Lawrence Nathan S, Thongngamdee Sompong, Wang Joseph, Lin Yuehe
Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003, USA.
Talanta. 2005 Jan 15;65(1):144-8. doi: 10.1016/j.talanta.2004.05.044.
A sensitive adsorptive stripping voltammetric protocol at a bismuth-coated glassy-carbon electrode for trace measurements of chromium (VI) in the presence of diethylenetriammine pentaacetic acid (DTPA) is described. The new protocol is based on accumulation of the Cr-DTPA complex at a preplated bismuth film electrode held at -0.80V, followed by a negatively-going square-wave voltammetric waveform. Factors influencing the stripping performance including the film preparation, solution pH, DTPA and nitrate concentrations, deposition potential and deposition time, have been optimized. The resulting performance compares well with that observed for analogous measurements at mercury film electrodes. A preconcentration time of 7min results in a detection limit of 0.3nM Cr(VI) and after 2min a relative standard deviation at 20nM of 5.1% (n = 25). Applicability to river water samples is demonstrated. The attractive behavior of the new "mercury-free" chromium sensor holds great promise for on-site environmental and industrial monitoring of chromium (VI). Preliminary data in this direction using bismuth-coated screen-printed electrodes are encouraging.
本文描述了一种在镀铋玻碳电极上的灵敏吸附溶出伏安法，用于在二乙烯三胺五乙酸（DTPA）存在下痕量测定铬（VI）。新方法基于Cr-DTPA络合物在预镀铋膜电极上于-0.80V下的富集，随后进行负向方波伏安波形测定。对影响溶出性能的因素进行了优化，包括膜制备、溶液pH值、DTPA和硝酸盐浓度、沉积电位和沉积时间。所得性能与在汞膜电极上进行类似测量时观察到的性能相当。7分钟的预富集时间导致铬（VI）的检测限为0.3nM，2分钟后在20nM时的相对标准偏差为5.1%（n = 25）。证明了该方法对河水样品的适用性。新型“无汞”铬传感器的诱人性能在现场环境和工业铬（VI）监测方面具有巨大潜力。使用镀铋丝网印刷电极在这方面的初步数据令人鼓舞。
