Zn(II)-selective membrane electrode based on tetra(2-aminophenyl) porphyrin

A new PVC membrane electrode for Zn2+ ions based on tetra(2-aminophenyl) porphyrin (TAPP) as membrane carrier is prepared. The sensor exhibits a linear stable response over a-wide concentration range (5.0 x 10(-5) to 1.0 x 10(-1) M) with a slope of 26.5 mV/decade and a limit of detection 3.0 x 10(-5) M (1.96 ppm). It has a response time of about 10 s and can be used for at least 8 months without any divergence in potential. The propose membrane sensor revealed good selectivities for Zn2+ over a wide variety of other metal ions and can be used in pH range of 3.0-6.0. It was successfully applied to the direct determination of zinc in a pharmaceutical sample and also as an indicator electrode in potentiometric titration of Zn2+ ions. (C) 2002 Elsevier Science B.V. All rights reserved.