Ru(terpy)-Based Conducting Polymer in Electrochemical Biosensing of Epinephrine

A heteroleptic [Ru(terpy)(2)](2+) (terpy = 2,2 ':6 ',2 ''-terpyridine) complex was electrochemically polymerized to give the corresponding metal-containing conducting polymer on gold and glassy carbon electrodes. The polymerization of the Ru(II) complex was allowed by a terthiophene functionalization on one of the two terpy coordinating fragments, whereas the presence of -COOH substituents on the second terpy ligand enabled the film to immobilize a tyrosinase enzyme by cross-linking with glutaraldehyde. Then, the Ru(terpy) conducting polymer worked as a transducer as well as an immobilizing agent in the design of amperometric biosensors for the determination of epinephrine. The electrochemical behavior of enzymatic sensors containing Ru(terpy)-based conducting polymers was investigated by differential pulse voltammetry and chronoamperometry. Analytical performances and kinetic parameters were calculated, suggesting a potential application of the reported biosensors in the determination of epinephrine in pharmaceutical products.