Ethanol content in must grape by alcohol dehydrogenase biosensors based on doped - Polyaniline modified screen printed electrodes

The presence of ethanol in wine grapes is an important parameter for the evaluation of their quality in winemaking. In this study we report the development of an amperometric biosensor for the determination of ethanol in must grape based on the alcohol dehydrogenase enzyme immobilized on polyaniline doped with poly(2-acrylamido-2-methyl-1-propane) sulfonic acid polymer. The doped polymer was able to detect ?-nicotinamide-adenine dinucleotide, reduced at low potential with a linear range from 0.005-2 mM and a sensitivity of 653.15 ?A M-1. Under optimized conditions, the alcohol dehydrogenase biosensor showed a limit of detection of 0.001 %vol ethanol and a sensitivity of 3551 nA %vol-1. Finally, the ethanol biosensor was used for ethanol determination in must from red and white wine grapes and matrix effect was evaluated.