Electrochemical investigations of potassium ferricyanide and dopamine by sodium dodecyl sulphate modified carbon paste electrode: A cyclic voltammetric study

A carbon paste electrode (CPE) modified by sodium dodecyl sulphate (SDS) was used for the detection of K3Fe(CN)6 and dopamine. Cyclic voltammetry (CV) demonstrated improved response of K3Fe(CN)6 and dopamine sensor at SDS/CPE compared to bare CPE. The effect of SDS concentration on the electrode quality also reveals that SDS formed a monolayer on a carbon paste electrode surface with a high density of negative charged end directed outside the electrode. On the formation of a SDS monolayer, the structure of the electrode interface changed significantly and the electrode/solution interface was replaced by the SDS monolayer/solution interface. The detection limit for K3Fe(CN)6 is 1 × 10−4 M and dopamine 1 × 10−7 M.