Interference-less vitamin C biosensor based on electrochemically prepared and encapsulated poly (aniline) into silicate network in mild acidic condition

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.