Voltammetric method using a lead film electrode for the determination of caffeic acid in a plant material

This paper deals with development of an adsorptive stripping voltammetric method for determination of caffeic acid (CA) at a lead film electrode (PbFE) The working electrode was prepared in situ on a glassy carbon substrate as a mercury-free" electrochemical sensor The method is based on the accumulation by adsorption of caffeic acid on PbFE and then the oxidation of CA during the stripping step In a acetate buffer based supporting medium the oxidation signal for caffeic acid was found to be proportional to the CA concentration in the range from 1 x 10(-8) to 5 x 10(-7) mol/L with the limit of detection equal to 4 x 10(-9) mol/L (with preconcentration for 30 s) The method operated in the square-wave voltammetric mode was successfully applied to the determination of CA in a plant material (herbs of Plantago lanceolata) The content of caffeic acid received by the proposed method was in close agreement with that obtained by high performance thin-layer chromatography (HPTLC) combined with densitometry This appears to be the first application of a lead film electrode to the determination of an organic compound in such complicated matrix (C) 2010 Elsevier Ltd All rights reserved