Water based homogenous carbon ink modified electrode as an efficient sensor system for simultaneous detection of ascorbic acid, dopamine and uric acid

Development of new sensor material suitable for simple, cost effective and quick practical application is a demanding research interest in electroanalytical chemistry. Carbon based inks prepared using different type carbon materials and binders as a gel or suspension have been often used as active sensor materials. Unfortunately, those systems are involved with complicated preparation route and usage of hazardous chemicals. Herein, we report a water based carbon ink composed of low cost carbon black powder, chitosan and acetic acid (prepared within 15 ± 2 min) for electrochemical sensor applications. A new carbon ink modified electrode was fabricated in this work by drop-casting of micro-litre quantity of the CB-Chit ink on a cleaned glassy carbon electrode (GCE) followed by air drying in room temperature for 10 ± 2 min. The CB-Chit ink modified GCE (GCE/CB-Chit) showed enhanced electrical conductivity, surface area and electrochemical activity than that of the unmodified GCE. Investigated simultaneous electrochemical oxidation and sensing of three biologically important molecules such as ascorbic acid, dopamine and uric acid on GCE/CB-Chit displayed excellent peak current signals at well-defined peak potentials with linear concentration ranges of 25-1600, 0.1-1400, and 5-1800 μM and detection limit of 0.1 μM (S/N = 3) for the all analytes. The newly fabricated sensor was validated by applying to the detection of AA, DA, and UA in vitamin C tablets, dopamine hydrochloride injection and human urine real samples. The sensor can be operated without any surface pre-treatment and analyte adsorption, unlike to the carbon nanotube and graphite based electrode systems with serious adsorption complications.

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