Electrochemical behavior and electrochemical determination of carbamazepine at an ionic liquid modified carbon paste electrode in the presence of sodium dodecyl sulfate

The electrochemical behavior and electrochemical determination of carbamazepine (CBZ) at a hydrophobic ionic liquid 1-benzyl-3-methylimidazole hexafluorophosphate ([BnMIM]PF6) modified carbon paste electrode ([BnMIM]PF6/CPE) in the presence of sodium dodecyl sulfate (SDS) were investigated. A well-defined and sensitive oxidation peak was observed at the [BnMIM]PF6/CPE in the presence of SDS and a 0.10 M phosphate buffer solution (pH 6.80). The oxidation peak current of CBZ increased significantly at the [BnMIM]PF6/CPE in the presence of SDS compared with that in the absence of SDS at the carbon paste electrode. It suggested that both SDS and [BnMIM]PF6/CPE show an obvious enhancing effect on the electrochemical oxidation of CBZ. The electrochemical kinetic parameters for CBZ at the [BnMIM]PF6/CPE in aqueous SDS solutions were also determined by chronocoulometry and chronoamperometry. Finally, the experimental conditions were optimized, and a new electrochemical method for the determination for CBZ was established. The oxidation peak current was linearly dependent on the CBZ concentration in the range 7.0 mu M to 0.7 mM, with a detection limit of 0.98 mu M (signal to noise ratio, S/N = 3). The relative standard deviation for six determinations of 0.10 mM CBZ was between 1.40 and 2.13 %. The proposed method was applied in the determination of CBZ in commercial tablet samples.