Gluconic acid determination in wine by electrochemical biosensing

The work describes an amperometric bienzymatic biosensor for gluconic acid based on the coimmobilization of gluconate kinase and 6-phospho- d -gluconate dehydrogenase by crosslinking with glutaraldehyde and bovine serum albumin onto screen-printed carbon electrodes. Experimental design methodology has been used to optimize immobilization and operational conditions. This method shows a reproducibility of 2.94% (n = 8) related to the slopes of calibration curves performed in the concentration range from 7.46 to 71.43 μM, as well as an average capability of detection of 7.46 for a probability of false positive and negative of 0.05. Finally, the developed biosensors have been successfully applied to gluconic acid determination in red wines. This approach represents an interesting alternative to be routinely used at a winery.