Abstract
The surface of an Au-disc electrode was modified through electro polymerization of aniline, in the presence of dodecyl benzene sulphonic acid (DBSA) and sulphuric acid (H2SO4) solution. The polymerization conditions were pre-optimized so that micelle formation and solution coagulation could be minimized and surfactant doped polyaniline film could be obtained through a quick, simple and one step polymerization route. The synthesized material was characterized via Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and cyclic voltammetry (CV). The effective surface area of the Au-disc, calculated through cyclic voltammetry, was immensely increased through a polyaniline (PANI) coating (0.04 and 0.11 cm2 for bare and PANI coated gold respectively). The modified electrode was utilized for ascorbic acid (AA) sensing. The changing pH of electrolyte and scan rate influenced the PANI electrode response towards AA. The modified electrode was highly selective towards AA oxidation and showed a very low limit of detection i.e. 0.0267 μmol·L–1. Moreover, the PANI coating greatly reduced the sensing potential for AA by a value of around 140 mV when compared to that on a bare gold electrode.
Highlights
Chemical sensors are of vital importance in different fields including monitoring of different species in the atmosphere, in industrial processes, biomedical analysis, and food quality control [1].Among many analytes, ascorbic acid (AA), which is an important biomolecule, is frequently detected as it is a main nutrient and antioxidant found in vegetables, fruits and in other naturally occurring systems [2]
We report here a very simple and reproducible way of electrode modification by electrooxidation of aniline in the presence of dodecylbenzene sulfonic acid (DBSA) and sulphuric acid (H2 SO4 ) solution
The surface of Au-disc electrode was modified with PANI by electro-oxidation of aniline in a single cell consisting of three electrodes (Scheme 1). 0.05M aniline was added to 1M H2 SO4 solution, sonicated for 10 to 15 minutes and was poured into 0.025M Dodecylbenzene sulfonic acid (DBSA) solution
Summary
Chemical sensors are of vital importance in different fields including monitoring of different species in the atmosphere, in industrial processes, biomedical analysis, and food quality control [1]. The conducting polymer polyaniline (PANI) has exceptional properties, including stable mechanisms of electrical conduction, reversible and simple doping–dedoping ability, easy synthesis, high environmental stability and low cost These properties make it a potential candidate for applications in electrochemical sensors [19,20,21]. It is supposed that PANI will have a large and adhesive surface area, and provide a conductive medium which will favorably support the dopant materials for their effective role in AA electro-oxidation These works show that PANI electrodes have a great potential to sense AA. Different characterization techniques support formation of PANI containing both DBSA and sulfuric acid as dopants This modified PANI electrode exhibits rapid electro-catalytic activity towards AA oxidation along with enhanced linearity, comparable low detection limit (LOD), high sensitivity and good selectivity
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