Electro polymerized 4-vinyl pyridine on 2B pencil graphite as ionophore for cadmium (II)

► UV–vis spectrum shows a strong absorption band at 420nm for Cd–4VP complex. ► Bright spots on electrode surface indicate the insertion of Cd within poly-4VP. ► The electrode prepared has a limit of detection of 1.0×10−7M Cd2+. ► The necessary plasticizer and additive is not used in the fabrication. ► Working pH range at 4.0–7.50 is significant for analysis of biological samples. A new poly(4-vinyl pyridine) (P4VP) based cadmium (Cd)-ion selective electrode (ISE) was developed. The 4-vinyl pyridine (4VP) was first polymerized electrochemically on the surface of graphite, later characterized by FTIR, SEM/EDX and then optimized as ISE for Cd. At optimal pH 6.4, slope of 27.7±0.8mVdecade−1, linear concentration range of 1×10−7 to 1.0×10−1M Cd2+ and limit of detection (S/N=3) of 2.51×10−8M were obtained. The ISE was very selective towards Cd2+, with Kpot