No abstract

A carbon ®ber microelectrode was modi®ed by electrodeposition of a polymeric coating of poly(3-methylthiophene) (P3MT) by cycling the potential between 0.0 and 1.7 V (vs. AgaAgCl). The electrochemical reduction of the herbicide metamitron in this kind of microelectrode was studied by applying several voltammetric techniques like cyclic voltammetry and square wave voltammetry. The cathodic stripping voltammetric response for metamitron was found to be dependent on the ®lm thickness, the accumulation time and on the pH of measurement medium. A good linear relationship between the cathodic stripping peak current and metamitron concentration was obtained over the range 1.0610, using a carbon ®ber microelectrode modi®ed with 15 coatings and 6 min preconcentration time at open circuit. The reproducibility of the measurements was satisfactory, RSD of 0.96 % (n 10) and the detectability achieved was of 2.83610 710 mol L 71.