Simultaneous determination of vitamins B2, B9 and C using a heterocyclic conducting polymer modified electrode

This paper illustrates the simultaneous determination of riboflavin (RB), ascorbic acid (AA) and folic acid (FA) at physiological pH by electrochemical method for the first time using the electropolymerized film of 3-amino-5-mercapto-1,2,4-triazole modified glassy carbon (p-AMTa) electrode. Bare GC electrode fails to show stable voltammetric signals for AA, RB and FA in a mixture due to the surface fouling caused by the oxidation products of them. In contrary, the p-AMTa electrode shows stable voltammetric signals for RB, AA and FA in a mixture with potential differences of 670 mV and 530 mV between RB-AA and AA-FA, respectively. Further, the p-AMTa electrode was used to selectively determine either of the vitamins individually in the presence of high concentrations of other two vitamins. When the concentration of RB was increased from 10 μM to 90 μM, AA was increased from 30 μM to 270 μM and FA was increased from 20 μM to 180 μM, the oxidation currents of the respective compounds increased linearly. The detection limit was found to be 4.54 × 10−8 M for RB, 7.14 × 10−7 M for AA and 2.5 × 10−7 M for FA (S/N = 3). The practical application of the present modified electrode was demonstrated by determining the concentrations of RB, AA and FA in human plasma samples.

► Electropolymerized functionalized triazole film was used to determine vitamins.
► It successfully separates the voltammetric signals of B2, C and B9 vitamins.
► Simultaneously determined B2, C and B9 vitamins by voltammetry for the first time.
► Selective determination of vitamins was also achieved.
► Practical application was demonstrated in human blood plasma.