ELECTROCHEMICAL APPROACH IN STUDYING THE INHIBITION OF ACETYLCHOLINESTERASE BY ARSENATE(III) - ANALYTICAL CHARACTERIZATION AND APPLICATION FOR ARSENIC DETERMINATION

The inhibition action of arsenate(III) on the activity of the enzyme a cetylcholinesterase immobilised on the surface of a graphite electrode is investigated, using an electrochemical approach. It is demonstrate d that the value of the registered amperometric signal depends on the AsO33--concentration. Parameters useful for the quantitative arsenate( III) determination (dynamic range, detection limit, sensitivity) are e valuated, pH dependencies and kinetic phenomena are discussed. A disti nction between As(III) and As(V) species is made. The method is applie d for estimating the arsenic contents in industrial waters after Cu2and Fe3+ elimination in the form of hydroxides. (C) 1998 Elsevier Scie nce B.V.