As a promising alternative for the mercury film electrode (MFE), the bismuth film electrode (BiFE) has been widely used in the field of electrochemical analysis. BiFE shows attractive properties and excellent performance such as environmentally friendliness, high sensitivity, easy preparation, well-defined signals and negligible effect to dissolved oxygen. According to recent experimental reports many electrochemical analysis have been studied with the use of BiFEs. Toxic heavy metal ions, pharmaceutical substances, pesticides and other biological molecules and products are determined with the BiFE. The voltammetric behavior of tannic acid (TA) at bismuth film modified glassy carbon electrode (Bi-GCE) has been studied by linear sweep voltammetry (LSV). Bismuth film was deposited on glassy carbon electrode (GCE) by single potential step chronoamperometric deposition at -450 mV for 120 s. TA shows a well-defined cathodic peak on the modified electrode at around -0.6 V vs. Ag/AgCl in Briton Robinson (BR) buffer solution of pH 3.6 at Bi-GCE. The effect of deposition time, deposition potential, bath concentration and pH of supporting electrolyte on the reduction current of TA were optimized. Under optimum conditions TA shows a linear range between 0.05 μM to 200 μM and the limit of detection (LoD) was found to be 0.035 μΜ. The developed method was used for determination of TA in tea samples.
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