Determination of copper at surface-modified electrodes: Effects of competitive binding and electrode size


Electrodes modified with electropolymerized films of [Ru(v-bpy)3]2+ into which Xylenol orange, Eriochrome cyanine R, Nitroso R salt or Bathocuproine sulfonate were incorporated by ion exchange can be used to determine copper in solution with high sensitivity, excellent linearity and a dynamic range of over two orders of magnitude. The presence of iron, cobalt, nickel, chloride or bromide does not alter the response measurably. Oxalate anions produce a steady increase in the current measured at the potential for oxidation of the copper complexes. The presence of phosphate anions in the preconcentration solution also gives rise to an enhanced signal. The use of modified microelectrodes (75 μm diameter) or ultramicroelectrodes (5 μm diameter) results in an enhancement in the sensitivity, although a saturation response is obtained for copperconcentrations above 6 × 10-6M. Ultramicroelectrodes modified with Bathocuproine sulfonate could be used in multiple determinations with good reproducibility (±9%) and without the need for remodification of the electrode surface. © 1993.

Publication Title

Journal of Electroanalytical Chemistry