Electrochemical Determination of Chlorophenols at Microcylinder Poly(3-methylthiophene) Modified Electrodes Based on a Previous Chemical Oxidation Using Bis(trifluoroacetoxy)iodobenzene
✍ Scribed by L. Agüí; B. Serra; P. Yáñez-Sedeño; A. J. Reviejo; J. M. Pingarrón
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 85 KB
- Volume
- 13
- Category
- Article
- ISSN
- 1040-0397
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✦ Synopsis
A sensitive electroanalytical method for the determination of chlorophenols (CPs) based on their chemical oxidation to the corresponding chlorobenzoquinones using bis(trifluoroacetoxy)iodobenzene (BTIB) is reported. The electrochemical monitoring of the chlorobenzoquinones is performed using cylindrical carbon fiber microelectrodes (CFMEs) modified with poly(3-methylthiophene) (P3MT) coatings. Variables involved in the oxidation of CPs by BTIB, such as the time needed for completion of the chemical oxidation, the influence of pH, of the supporting electrolyte concentration, and of the BTIB amount were optimized. Square-wave voltammetry at a P3MTcoated CFME allowed the obtention of detection limits of around 2.0610 À7 mol L À1 for the different CPs. The amperometric detection of the CPs at P3MT-coated CFMEs was carried out under flow-injection conditions by using a flow-cell specially adapted for the use of microelectrodes. Taking into account the best signal-to-noise ratio, a potential of 0.20 V was selected for the amperometric detection. Under the optimized conditions, no evidence of modified microelectrode fouling was observed and no cleaning or regeneration pretreatment was needed when working with the same polymer modified microelectrode during the whole working day. The limits of detection obtained by FI with amperometric detection were close to 5610 À8 mol L À1 .