Electrochemical biosensor based on protein-polysaccharide hybrid for selective detection of nanomolar dopamine metabolite of 3,4-dihydroxyphenylacetic acid (DOPAC)

A strategy for the preparation of tyrosinase biosensor has been proposed to determine dopamine metabolite of 3,4-dihydroxyphenylacetic acid (DOPAC). An amino-polysaccharide chitosan was successfully used as matrix to entrap tyrosinase on glassy carbon electrode surface on basis of tyrosinase conjugated with chitosan. The sensor was operated at −0.15 V. The current linearly increased with the increasing concentration of DOPAC over the concentration of 6 nM to 0.2 mM. The sensor can be used to selectively determine nanomolar DOPAC in the presence of physiological level of ascorbic acid (AA), uric acid (UA), acetaminophen, neurotransmitters including dopamine, l-dopa, adrenaline and noradrenaline.