Spectroelectrochemical Detection of Acetaldehyde in Wines

Abstract

The combination of electrochemical sensors and spectroscopy has been scarcely used due to the traditional instrumental limitations of spectroelectrochemical techniques. However, the development of new setups and commercial instruments enables the spectroelectrochemical detection of a variety of analytes [1]. In that way, UV-Vis spectroelectrochemistry joins the advantages of electrochemistry and UV-Vis spectroscopy, improving the analytical features that both techniques have separately.In this work, a new spectroelectrochemical two-enzyme sensor system has been developed for the detection of acetaldehyde in wine. Spectroelectrochemical detection is achieved by the analysis of the optical properties of the ferri/ferrocyanide redox couple involved in the enzymatic process: aldehyde dehydrogenase catalyzes the aldehyde oxidation using NAD+ as a cofactor and, simultaneously, diaphorase reoxidizes the NADH formed in the first enzymatic process due to the presence of ferricyanide. The analysis of the characteristic UV-Vis bands of ferricyanide at 310 and 420 nm allows the detection of acetaldehyde, since absorption bands are only related to the oxidation of this substrate and avoids the contribution of other interferents [2]. Two different wines have been evaluated in this work, obtaining excellent results that agree with the literature as well as with those obtained with a commercial fluorogenic kit.