FIA of Phenol and Pentachlorophenol at Glassy Carbon Electrode in Oxidative Mode

Flow injection analysis (FIA) method for phenol and pentachlorophenol at glassy carbon electrode has been developed. Effect of supporting electrolyte concentration and its nature, effect of sample and ground electrolyte pH, influence of flow rate and passivation of glassy carbon electrode were studied. It was found that an appropriate concentration of supporting electrolyte is required for a better sensitivity of analyte. Phenol and pentachlorophenol can be efficiently analyzed at pH 7. Flow rate between 0.5 to 1.0 ml/ min is optimum for the analysis. Working electrode activity can be regenerated by keeping it at - 0.8V for ten minutes in the flow stream of ground electrolyte. Detection limits for phenol and pentachlorophenol without a preconcentration step is 40 and 100 µg / L respectively and their relative standard deviation (RSD) is around six (N = 4) and four (N = 4) respectively. The former can be improved by incorporating solid phase extraction/ preconcentration that will lower it to hundred times. The proposed method is simple, sensitive and above all selective.