Highly Selective All‐Plastic, Disposable, Cu²⁺‐Selective Electrodes

Conducting polymers (CP) remain a promising material to construct stable potential all‐solid‐state ion‐selective potentiometric electrodes. The unique properties of poly(3,4‐ethylenedioxythiophene) doped with poly(4‐styrenesulfonate) ions, PEDOT‐PSS: high CP stability and affinity of doping anions towards Cu 2+ ions, make it highly attractive for construction of all‐solid‐state copper(II)‐selective electrodes with outstanding selectivity. The additional benefits can arise from solution processability of commercially available PEDOT‐PSS system. This material was highly promising for a new sensor arrangement, i.e. to obtain disposable, planar and flexible all‐plastic Cu 2+ ‐selective electrodes. These sensors can be obtained by casting a commercially available dispersion of PEDOT‐PSS (Baytron P) on a plastic, non‐conducting support material. The CP being both electrical lead and ion‐to‐electron transducer, was covered with plastic, solvent polymeric Cu 2+ selective membrane. This extremely simple arrangement, after conditioning in dilute Cu 2+ solution, was characterized with linear Nernstian responses within the activities range from: 0.1 to 10 −4 M, followed by super‐Nernstian responses for lower activities. The latter result points to effective elimination of primary ions leakage from the plastic membrane / transducer phase and has resulted in significantly improved selectivities. Obtained log K Cu,Jᵖᵒᵗ values were equal to −7.6 for Co 2+ , −7.4 for Zn 2+ , −7.2 for Ca 2+ and −6.8 for Na + , respectively.