Highly selective and sensitive copper(II) membrane coated graphite electrode based on a recently synthesized Schiffs base

A PVC membrane electrode based on bis-2-thiophenal propanediamine (TPDA) coated directly on graphite is described. The electrode exhibits a Nernstian response for Cu2+ over a very wide concentration range (1.0×10-1 to 6.0×10-8M) with a detection limit of 3.0×10-8M (2.56ngml-1). It has a fast response time and can be used for at least 2months without any major deviation. The proposed sensor revealed very good selectivities for Cu2+ over a wide variety of other metal ions and could be used in the pH range of 3.0-7.0. It was successfully used for direct determination of copper in black tea and as an indicator electrode in potentiometric titration of copper ion.