CHARACTERISTICS OF COPPER(II) ION-SELECTIVE ELECTRODE BASED ON AQUATIC HUMIC SUBSTANCES

A carbon rod electrode coated with a poly(vinyl chloride) (PVC) membra ne containing aquatic humic substances (HS) isolated from swamp water was constructed for the detection of copper(II) ion. The electrode exh ibits a linear response with a slope of 60.1 +/- 2.0 mV/decade in conc entration range from 10(-5) mol L-1 to 10(-2) mol L-1. The detection l imit for the copper(II) ion was estimated to be of 1 x 10(-5) mol L-L. Electron spin resonance spectroscopy (ESR) and pH titration results i ndicated that the humic substances interact with copper(II) ions to fo rm complexes. These results confirm that the potential response of the membrane electrode with good sensitivity, selectivity except for Pb2 and Hg2+, and response to copper(II) ion is due to the formation of s table complexes occurring at the electrode surface.