DETERMINATION OF COPPER IONS IN WATERS BY ELECTROCHEMICAL STRIPPING CHEMILUMINESCENCE ANALYSIS IN-SITU

A novel stripping chemiluminescence (CL) method in situ has been devel oped which is a combination of selective stripping and CL detection in situ, This method consists of a concentration (pre-electrolysis) step , in which the analyte metal ion is reduced at a controlled potential whilst being deposited as the metal on a solid electrode placed in an electrogenerated chemiluminescence flow cell, a subsequent media excha nge step and finally the stripping-CL step, in which the CL emission o n the electrode surface is detected in situ when the C:L reagent solut ion is delivered into the cell to react with the metal ion which has j ust been stripped by oxidization, The concentration of analyte is quan tified by CL intensity. Copper ion as a representative analyte was inv estigated using constant potential stripping and CL detection of a lum inol-copper(II)-cyanide system. The response to the concentration of c opper is linear in the range 0.040-40 mu g dm(-3) and an extremely low detection limit of 0.02 mu g dm(-3) can be achieved in a deposition t ime of 2 min. The method developed has been applied successfully to th e determination of copper in water samples. The method shows excellent selectivity and sensitivity compared with the associated CL and squar e wave anodic stripping voltammetry method.