Determination of polyphenol ‘pool’ in olive oil mill waste water using a tyrosinase biosensor operating in aqueous solution or in organic solvent

Abstract

Biosensors are very versatile devices that can be used to solve various kinds of problem that are increasingly found in the various branches of chemistry, particularly in the fields of foodstuffs and the environment. In recent years, there has been considerable development in a new biosensor sector, that of OPEEs (organic phase enzyme electrodes). These are biosensors able to function also in organic solvents or in mixtures of several different organic solvents. One of these enzymatic biosensors that has recently proved to be particularly versatile is the tyrosinase biosensor, of which several different versions have been developed. Our group in particular has in recent years developed both a version that operates in aqueous solutions and one suitable for organic solvents. These tyrosinase biosensors are essentially made up of an amperometric transducer for oxygen (Clark type), coupled with the tyrosinase enzyme, which is suitably immobilized according to the solvent in which it must operate. In this article the possibility was assessed of using them to determine the polyphenol ‘pool’ in olive oil mill wastewater. The method has been optimized as regards both the solvent and the type of enzymatic immobilization to be used. Results have been compared with those obtained using the Folin–Ciocalteau method, which is chosen as reference method.