Development of a polypyrrole-based amperometric phosphate biosensor

Abstract

A biosensor is developed by co-entrapment of Purin Nucleoside Phosphorylase (PNP) and xanthine oxidase (XOD) and potassium ferrocyanide (K4Fe(CN)6 into a polypyrrole (PPy) film via., galvanostatic polymerisation of pyrrole. The optimum conditions for formation of the Ppy-PNP-XOD-Fe(CN)64- film are 0.3 M pynole. 6.2 UmL-1 XOD, 49 UmL-1 PNP, 40 mM K4Fe (CN)6, polymerisation period of 200 sec and an applied current density of 0.5 mA cm-2. The optimum potential for the amperometric biosensing of phosphate was 200 mV vs. Ag/AgCl (3 M KCl) in 0.05 M barbitone buffer. The achievable linear concentration range was between 0.1 and 1 mM, while the minimum detectable amount was 10 μM. © 2009 Asian Network for Scientific Information.