Amperometric detection of polyphenols using peroxidase-immobilized gold electrodes

Horseradish peroxidase (HRP) is covalently immobilized on a self-assembled monolayer of mercaptopropionic acid on vapor-deposited gold electrode. The electrode allows the polyphenol detection down to 2 mu mol dm(-3) with a li near relationship up to 25 mu mol dm(-3). The reduction current of oxidized polyphenol intermediate formed during the enzymatic reaction in the presen ce of H2O2 is proportional to the concentration of polyphenol. The present method is applicable to the determination of the total polyphenol content i n wine and tea.