Electrocatalysis of SDS Surfactant Modified Carbon Paste Electrode for the Simultaneous Determination of Ascorbic Acid, Norepinephrine and Folic Acid

A carbon paste electrode was modified with anionic surfactant sodium dodecyl sulphate (SDS) solution by immobilization method; surfactant solution was strongly adsorbed on the carbon paste electrode (CPE) and applied to the simultaneous detection of norepinephrine (NE) in the presence of ascorbic acid (AA) and folic acid (FA). The electrochemical response of the SDS modified CPE (SDS/CPE) was evaluated with respect to pH, preconcentration time, scan rate and other variables by cyclic voltammetric technique. The concentration variation of SDS (modifier) results in optimization of the modified electrode and also the good electrocatalytic performance of the SDS/CPE were tested on the redox behavior of the potassium ferricyanide. The present method provided a simple method for the detection of NE in biological samples. Electron transfer of NE redox at bare carbon paste electrode was too slow as compared at SDS/CPE. The SDS/CPE showed reversible electrochemical behavior of NE with a formal potential of 0.065 V versus SCE. The interfacial process between the SDS/CPE and NE in 0.2 M PBS (pH 7.0) was investigated with their electrochemical reaction and the results indicated that the two electron two proton transfer was involved in the electrode reaction process. Under optimal conditions a detection limit of 1 μM was obtained