Abstract
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•The Silica-PANI electrode was prepared by simple electro-polymerization method.•The electroactivity of the electrode can be extended from acidic to highly basic.•It showed catalytic activity towards oxidation of Vitamin C.•A linear response of Vitamin C was obtained in the range from 10 μM to 60 μM.•The sensitivity is 5 nA/μM with almost diminished response to interferences.
Extending electroactivity of the silica-poly(aniline) (Silica-PANI), prepared by electro-polymerization of N-[3-(trimethoxysilyl)propyl] aniline (TMSPA) monomer, to the highly basic pH is presented. The electrochemical reversibility of the Silica-PANI and the regeneration of its electroactivity are confirmed by the results of cyclic voltammetry (CV). The electro activity of the Silica-PANI electrode extended to highly basic condition, even at pH 13 and it was confirmed using UV–visible spectroscopy. In addition, the regeneration of electroactivity of Silica-PANI electrode was verified in HCl solution, before and after cycling the electrode in KOH solution for 50 cycles. The electrode retains its electrochemical reversibility, demonstrating that Silica-PANI electrode is not influenced by KOH solution and chemically stable. Electrocatalytic activity of Silica-PANI electrode was investigated and it displays catalytic activity towards oxidation of Vitamin C (ascorbic acid, AA). Using the Silica-PANI electrode, the amperometric measurements were performed at an applied potential of 0.07 V and a linear response of Vitamin C was obtained in the range from 10 μM to 60 μM and sensitivity of 5 nA/μM. Interference studies for Vitamin C at Silica-PANI electrode were also examined using electroactive biomolecules such as dihydronicotinamide adenine dinucleotide (NADH), dopamine (DA), uric acid (UA) and H2O2, respectively. It uncovered that almost diminished response of its interference for Vitamin C at Silica-PANI electrode.