Electrochemically Generated Recognition Sites in Self-doped Polyaniline Modified Electrodes for Voltammetric and Potentiometric Determination of Copper(II) Ion

Chemical recognition elements for copper(II) ion have been generated in electrodes modified with poly(aniline-co-metanilic acid), P(An-co-MA), membrane and the resulting electrodes were used as selective sensors for voltammetric and potentiometric determination of this ion in an extended pH range. The P(An-co-MA) membrane was electrodeposited from aqueous mixed monomer solutions of An and MA, without the presence of a supporting electrolyte. For generating the recognition elements, P(An-co-MA) modified electrodes were subjected to several consecutive reduction/oxidation potential steps in copper(II) ion solution. It seems that during these potential steps, the receptor sites of the membrane are adjusted to the size, complexing property and hard/soft nature of copper(II) ion. This electrochemically mediated templating process, provided a selective sensor for determination of copper(II) ion. The results of preconcentration/differential pulse anodic stripping voltammetry, indicated analytical relation between the peak current and concentration of copper(II) from 1.0x10(-9) to 1.0x10(-4)M. The interference effect of various metal ions was explored and it was found that only mercury and silver ions show a considerable interference. The sensor exhibited selective potentiometric response for copper(II) over a wide concentration range (1.0x10(-8) to 1.0x10(-3)M) with a Nernstian slope of 27.9 +/- 0.3mV per decade of copper(II) ion activity.