AMPEROMETRIC BIOSENSING OF COPPER(II) IONS WITH AN IMMOBILIZED APOENZYME REACTOR

Novel amperometric biosensing is proposed for the determination of copper(II) ions by an apoenzyme sensor in flow streams. The biosensing system was assembled with an immobilized galactose oxidase reactor and flow-through electrochemical devices for monitoring the enzymatic activity. Copper(II) ions were selectively determined in the range 0.1 to 10 mM through activation of the immobilized metal-free galactose oxidase (apoenzyme) reactor. The activity was assessed by injection of d-galactose solution (0.1 ml, 40 mM) and then the consumption of dissolved oxygen by the oxidative reaction or the production of hydrogen peroxide enzymatically generated was measured independently by a polarographic oxygen electrode or a membrane-covered Pt/Ag/AgCl electrode pair. Regeneration of the reactor was carried out by pumping 10 mM N,N-di-ethyldithiocarbamate solution (pH 8.0) between successive samples. © 1990.