Journal of University of Science and Technology of China ›› 2014, Vol. 44 ›› Issue (8): 637-647.DOI: 10.3969/j.issn.0253-2778.2014.08.002
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ZHAO Qiping
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Abstract: A sensitive Bi/MWCNTs (multi-walled carbon nanotubes) composite film modified electrode was fabricated by two-step electrodeposition. First, the MWCNTs were electrodeposited instead of dropping coated on the glass carbon electrode(GCE), and the bismuth film was then deposited on the MWCNTs/GCE. A protocol used for the determination of total chromium and hexavalent chromium in water by square wave cathodic adsorptive voltammetry in the presence of cupferron (N-nitroso-N-phenylhydroxylamine ammonium salt) was proposed. In the presence of cupferron, Cr(Ⅲ) can form the complex with cupferron and be accumulated on the surface of the modified electrode by adsorption at a potential of -035 V, and then is reduced with the cathodic scan from -035 V to -110 V. An accumulation time of 2 min results in a detection limit of 005 μg/L Cr(Ⅵ) and a relative standard deviation of 52% (n=75) for 10 μg/L. Application to river water samples is demonstrated. The total chromium can be directly determined by standard addition of Cr(Ⅲ) or Cr(Ⅵ); the Cr(Ⅵ) can be separated with Cr(Ⅲ) by using an anion trapping column and then determined by standard addition of Cr(Ⅵ). The results are consistent with those detected by ICP-MS (inductive coupled plasma mass spectrometry). The attractive behavior of the new “mercury-free” chromium sensor holds great promise for on-site environmental and industrial monitoring of chromium.
Key words: Bi/MWCNTs (multi-walled carbon nanotubes) modified electrode, square wave cathodic adsorptive voltammetry, chromium, speciation analysis, cupferron
ZHAO Qiping, WU Shouguo, ZHANG Zhixin, ZHOU Lei. Catalytic adsorptive stripping determination of trace chromium based on the bismuth/MWCNTs modified electrode[J]. Journal of University of Science and Technology of China, 2014, 44(8): 637-647.
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URL: http://just-cn.ustc.edu.cn/EN/10.3969/j.issn.0253-2778.2014.08.002
http://just-cn.ustc.edu.cn/EN/Y2014/V44/I8/637