Direct electrochemistry and voltammetric determination of midecamycin at a multi-walled carbon nanotube coated gold electrode.
Colloids Surf B Biointerfaces 2011;
86:247-50. [PMID:
21543194 DOI:
10.1016/j.colsurfb.2011.03.037]
[Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Revised: 03/25/2011] [Accepted: 03/29/2011] [Indexed: 11/23/2022]
Abstract
Macrolide antibiotics generally shows slow electron-transfer rate and produces insensitive redox peaks at conventional electrodes. In this paper, we studied the electrochemical behavior of midecamycin, one of macrolide antibiotics, at a multi-walled carbon nanotube (MWNT) modified gold electrode. It was found that MWNT could adsorb midecamycin and promote its direct electron-transfer. Hence midecamycin exhibited a more sensitive anodic peak at the modified electrode. The electrochemical process showed the feature of a mixed-control system of diffusion and adsorption. Under the optimized conditions (i.e. pH 7.0 phosphate supporting electrolyte, 5 μl 0.5 mg ml⁻¹ multi-walled carbon nanotube suspension for Ø = 2.0 mm electrode, accumulation at -0.8 V for 150 s), the anodic peak current was linear to midecamycin concentration in the range of 5 × 10⁻⁷ to 2 × 10⁻⁵M, with a correlation coefficient of 0.998. For a 5×10⁻⁶ M midecamycin solution, ten repetitive measurements gave a relative standard deviation of 2.2%. This method was successfully applied to the determination of midecamycin in medicine tablet and the recovery was 97.5-104.0%.
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