Preparation of Modified Electrode using Toluidine Blue O and Molybdenum Schiff Base Complex for Detection of Dopamine in the presence of Ascorbic Acid

The complex cis-dioxo-bis[3-methoxy-2,2-dimethylpropanediamine] molybdenum(VI) (cis-[Mo(O)(2)L]) and toluidine blue O (TBO) are used for modification of carbon paste electrode (CPE). In order to study of the electrochemical behavior of ascorbic acid (AA) and dopamine (DA) at the surface of the modified CPEs, the differential pulse and cyclic voltammetric methods (DPV and CV) were used. These results reveal that by application of the modified CPE a peak resolution about 329 mV is obtained for AA and DA and the limits of detection (S/N=3) were 1x10(-7) M and 4x10(-7) M for DA and AA, respectively. Surface regeneration and the very easy preparation of the modified CPE together with the very good peak resolution and sub-micromolar detection limits designate the prepared CPE in this work appropriate for simultaneous voltammetric determination of DA and AA. The modified CPE was used successfully for recovery of the analytes in human plasma samples.