Screen-printed biosensors for the control of wine quality based on lactate and acetaldehyde determination

Biosensors for D-lactate and acetaldehyde were developed, based on screen-printed electrodes and NAD(+)-dependent dehydrogenases. Modification of screen-printed electrodes with the mediator Meldola Blue or with Meldola Blue-Reinecke salt resulted in sensitive, low cost and reliable NADH detectors. The biosensors were realised in two configurations, as disposable and reusable devices. Single-use sensors were obtained by simple deposition of enzyme and cofactor on the surface of mediator-modified electrodes. Chronoamperometry was used for the detection of substrates in small volumes of samples (25 mul). Immobilisation of dehydrogenases by entrapment in poly(vinyl alcohol) bearing styrylpyridinium groups (PVA-SbQ) allowed sensors to be obtained with sufficient operational stability. Amperometry in stirred solutions was the detection technique with biosensors for multiple use. The 3sigma detection limits for acetaldehyde were 1 muM by amperometry and 6 muM by chronoamperometry and for D-lactate-0.03 muM and 0.05 muM for reusable and disposable biosensors respectively. The biosensors were applied in the analysis of some French and Romanian wines. (C) 2002 Elsevier Science B.V. All rights reserved.