PANI sensor for monitoring the oxidative degradation of wine using cyclic voltammetry.

Redox species in wine are altered by pH and some wines are easily degraded due to oxidation and sulfur dioxide (SO2) reduction. There is a need for quick, easy, simple, and economical methodologies for pH and wine-oxidized products (acetaldehyde) analysis. This study aimed to measure pH and degradation of wines that were electrochemically analyzed using polyaniline (PANI) sensor. Gas chromatography (GC) and fourier transform infrared spectrometer (FT-IR) were also used. Electrochemical analysis showed that oxidation was accelerated and peak currents (Ip,a) and potentials (Ep,a) shifted to negative direction due to acetaldehyde formation. PANI sensor achieved a limit of detection (LOD) of 7 × 10-1 ppm and a sensitivity of 5.20 µA ppm-1 cm-2. Acetaldehyde formation was confirmed by GC (30%) and FT-IR spectra at 1647 cm-1 to the CO vibration of aldehyde. These results suggested that acetaldehyde degraded the taste of wine after remaining open.