Ethanal Assay, Using an Enzymo-Conductimetric Method

Abstract

An enzymo-conductimetric method for the assay of ethanal is described. It is based on ethanal oxidation in presence of yeast aldehyde dehydrogenase. Experimental conditions compatible with conductimetry were optimized and kinetic parameters of the enzymatic reaction determined. Due to the low K_M value of ethanal for the enzyme, an end-point assay was proposed. A linear relationship was demonstrated between experimental conductance changes and ethanal concentration up to 25 μM. Validation of the assay was made on wines by comparison with a spectrophotometric method. Both methods gave similar results, but conductimetry avoids sample treatment if solutions are coloured or turbid.