Rapid determination of Cadmium: A Potentiometric Membrane Sensor based on Ninhydrin-Pyrogallol monoadduct as a New Ionophore

In this study, a Cd2+ potentiometric ion selective membrane sensor was prepared based on the selective complexation between 4b,6,7,9b-Tetrahydroxy-4bH-indeno[1,2-b]benzofuran-10(9bH)-one(ninhydrin-pyrogallol monoadduct) as ionophore and Cd2+ ion. The electrode exhibits a Nernstian response for Cd2+ ion over a concentration range of 1.0×10-1 to 1.0×10-4 mol L-1 with a slope of 28 mV per decade. The limit of detection of the sensor is 7.0×10-5mol L-1. The sensor has a relatively fast response time (∼5 s) and a useful working pH range of 3.0–7.0. Interference of some cations was also evaluated. It was used as an indicator electrode in potentiometric titration of Cd2+ with EDTA and in direct determination of Cd2+ in water and wastewater samples. The results indicate that this electrode is sensitive for determination of Cd2+.