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

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 ± 0.8 mV decade−1, linear concentration range of 1 × 10−7 to 1.0 × 10−1 M Cd2+ and limit of detection (S/N = 3) of 2.51 × 10−8 M were obtained. The ISE was very selective towards Cd2+, with Kpot < 1 × 10−2 in the presence of the usual cations and anions in water samples. Response time and shelf life of less than 1 min and 90 days, respectively, were observed. Its application was tested in various types of samples.