A novel conducting polymer based platform for ethanol sensing

•Synthesis of a novel monomer for production of a functional conducting polymer.•Covalent immobilization for excellent enzyme immobilization.•Sensitive and reliable alcohol biosensor.•Effective application for the determination of ethanol in commercial alcoholic beverages. A new amperometric ethanol biosensor was fabricated for sensitive and rapid analysis of ethanol. For this purpose, a novel monomer, 9-methyl-9H-carbazole-3-carbohydrazine (MCCH), was designed and electrochemically polymerized on a graphite electrode to achieve a conducting and effective immobilization matrix for enzyme immobilization. Due to the presence of amino groups in the structure of conducting polymer, alcohol oxidase molecules were covalently immobilized onto the functional polymer which brought an effective and long-life analysis of the substrate, ethanol. N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) chemistry was used for linking carboxylic acid groups of the enzyme molecules with amino groups of the polymer. After successful immobilization, amperometric biosensor responses were recorded at −0.7V vs. Ag/AgCl in phosphate buffer (pH 7.0). KMapp (8.74mM), Imax (5.94μA), LOD (0.131mM) and sensitivity (4.79μAmM−1cm−2) values were determined. Finally, the prepared biosensor was successfully applied for determination of ethanol content in alcoholic beverages.