Co2+-selective membrane electrode based on the Schiff base NADS

A new PVC membrane electrode for cobalt(II) ions based on a recently synthesized Schiff base of 5-((4-nitrophenyl)azo)-N-(2',4'-dimethoxyphenyl)salicylaldimine is reported. The electrode exhibits a Nernstian response for Co2+ ions over a wide concentration range (9.0X10(-7)-1.0x10(-2) M) with a slope of 29( I). The limit of detection is 8.0x10(-7) M. The proposed sensor revealed good selectivities over a wide variety of other cations including hard and soft metals. This electrode could be used in a pH range of 3.5-6.0. It was used as an indicator electrode in potentiometric titrations of cobalt(II) ions and can be used in the direct determination of Co2+ in aqueous solutions.