Biosensor based on acetylcholinesterase for acetylthiocholine amperometricdetection at low applied potential

The electrochemical behaviour of thiocholine on different electrode materia ls (platinum, graphite, glassy carbon and carbon paste), in the absence or in the presence of cobalt(II) phtalocyanine (CoPC), was investigated by cyc lic voltammetry in view of construction of an acetylcholinesterase (AChE) b ioelectrode, working in the optimum potential range for amperometric detect ion. A comparison between the kinetic parameters of the amperometric respon se to acetylthiocholine (ASChCl) for Pt-AChE and Pt-CoPC-AChE bioelectrodes revealed the electrocatalytical effect of CoPC. Based on this effect it wa s found that for Pt-CoPC-AChE bioelectrode the applied potential can be sig nificantly lowered (from +410 mV to +150 mV vs. Ag/AgCl, KClsat), in order to diminish the electrochemical interferences. susceptible to occur in comp lex matrix analysis.