Electroanalytical Determination of Copper(II) Ions Using a Polymer Membrane Sensor

In this study, a new potentiometric sensor selective to copper(II) ions was developed and characterized. The developed sensor has a polymeric membrane and contains 4.0% electroactive material (ionophore), 33.0% poly(vinyl chloride) (PVC), 63.0% bis(2–ethylhexyl)sebacate (BEHS) and 1.0% potassium tetrakis(p–chlorophenyl)borate (KTpClPB). This novel copper( II)–selective sensor exhibits a Nernstian response over a wide concentration range from 1.0×10⁻⁶ to 1.0×10⁻¹ mol L⁻¹ with a slope of 29.6 (±1.2) mV decade⁻¹, and a lower detection limit of 8.75×10⁻⁷ mol L⁻¹. The sensor, which was produced economically by synthesizing the ionophore in the laboratory, has a good selectivity and repeatability, fast response time and stable potentiometric behaviour. The potential response of the sensor remains unaffected of pH in the range of 5.0–10.0. Based on the analytical applications of the sensor, we showed that it can be used as an indicator electrode in the quantification of Cu²⁺ ions by potentiometric titration against EDTA, and can also be successfully utilized for the determination of copper(II) ions in different real samples.