Effect of cetyltrimethyl ammonium bromide (CTAB) in determination of dopamine and ascorbic acid using carbon paste electrode modified with tin hexacyanoferrate.

The cationic surfactant, cetyltrimethyl ammonium bromide (CTAB) effect on accurate determination of dopamine in the presence of ascorbic acid (as natural obtrusive in determination of dopamine) using chemically modified electrode based on tin hexacyanoferrate (SnHCF) as a modifier at carbon paste electrode (CPE) is described. The electrochemical response of bare CPE and SnHCF modified electrode (ME) examined in different pHs, in absence and presence of different concentration of dopamine (DA) and ascorbic acid (AA). In addition a simple and reliable method for simultaneous electrochemical determination of AA and DA was presented. It was based on the use of the cationic surfactant CTAB that enables the separation of the oxidation peaks potential of AA and DA. The experimental results showed that DA and AA have two separate peaks. In pH 3 and at presence of 3mM of CTAB the separation of DA and AA peaks and the eminence of them increased evidently. Good linear response to AA and DA was observed in the range of 0.4-50 and 0.2-25mM with the correlation of 0.9912 and 0.9955, respectively.