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

► UV-vis spectrum shows a strong absorption band at 420 nm 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 × 10−7 M 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.