Voltammetric and Potentiometric Determination of Cu2+ Using an Overoxidized Polypyrrole Based Electrochemical Sensor

Electropolymerization of pyrrole using an anionic sulfosalicylic acid ligand on the surface of electrode followed by overoxidation of membrane is performed to design a new modified electrode (ME) to measure specifically Cu2+ via complexation and intrusion of copper ion into the polymeric membrane. Copper binding property of ligand, overoxidation, and applied potential and polymeric structure of the modified electrodes are factors that encourage binding performance of Cu2+ into polymeric membrane of the electrode and lowering the detection limit. Presence of Cu2+ into the membrane was approved by Energy Dispersive Analysis X-Ray. Preconcentration of the analyte into modified electrode followed by differential pulse anodic stripping voltammetry is used to detect and measure Cu2+ quantitatively. Potentiometric measurements were conducted to test the ability of electrode to act as an ion selective for the direct measurement of Cu2+. Two interfering elements were Ag and Hg, but other elements such as Ni2+, Al3+, Zn2+, Ba2+, Mn2+, Co2+, Cd2+, and Pb2+even with 100 times more concentrated than analyte did not interfere. The electrode showed stable and reproducible surface with RSD less than 0.9%, range of linearity was from 1.0 × 10–8 to 1.0 × 10–3 M with a detection limit of 1.5 × 10–9 M. In the case of potentiometric measurements, RSD = 0.4%, linearity from 1.0 × 10–8 to 1.0 × 10–3 M, detection limit about 4.0 × 10–9 M and response time was 8 to 40 s.

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