Voltammetric Sensor Based on Nano TiO Powder Modified Glassy Carbon Electrode for Determination of Dopamine

ABSTRACT

Synthesis of TiO₂ nanopowder via a low cost ultrasonic spray pyrolysis technique is reported and the nanopowder is used for the surface modification of glassy carbon electrode. The structural characterization of nanopowder by high temperature XRD clearly shows the phase transformation from anatase to rutile phase on increasing temperature. The morphological structure is characterized by field emission scanning electron microscope and high resolution transmission electron microscope. The modified electrode is used for the determination of dopamine in the presence of excess of ascorbic acid/ uric acid using square-wave voltammetry. The voltammograms obtained during the oxidation studies revealed that nano TiO₂ exhibits better catalytic function towards the oxidation of dopamine and ascorbic acid/uric acid. The overlapping voltammetric response of all the biomolecules at the bare electrode gets resolved into well defined voltammetric peaks with lowered oxidation potential and enhanced oxidation currents. Linear calibration curves for dopamine are obtained over the concentration range 75 nM - 2.5 μM in 0.1M phosphate buffer solution at pH 7.2 with a correlation coefficient of 0.9940 and the detection limit (3σ) is estimated to be 13.8 nM.

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