Sensor based on electrosynthesised imprinted polymeric film for rapid and trace detection of copper(II) ions

Herein we report the fabrication, characterisation and application of a novel voltammetric sensor based on an electrosynthesised ion imprinted polymer (IIP) film for the determination of copper(II) in water samples. This sensitive and highly selective sensor was prepared by electropolymerisation of p-phenylenediamine in the presence of Cu2+ as template, combined with the screen-printed technology for the transducer element. Electrochemical methods were used to control the electropolymerisation process, the template removal and the subsequent rebinding. The electrosynthesised film on the surface of screen-printed platinum electrodes was characterised by cyclic voltammetry (CV), scanning electron microscopy (SEM), and FTIR-ATR analysis. The incubation of the IIP-modified electrode with Cu2+ resulted in an increase of the redox properties of the obtained polymer. The performance of the proposed sensor was observed in acetate buffer (50 mM, pH = 5) over the Cu2+ concentration range 0.95–244 nM, with a limit of detection of 2.7 nM. The multivariate approach was employed in order to evaluate the influence of four variables on the sensitivities of the imprinted sensor towards the template. The IIP sensor showed high affinity to copper in comparison with the non-imprinted polymer (NIP). The reproducibility of the sensor was evaluated on five different sensors and it was estimated as 7.75 % (RSD). Selectivity studies were performed against several potential interferents, such as Ni2+, Mn2+, Ag+, Hg2+, Zn2+, Co2+, Pb2+ and Cd2+ ions. The application of the proposed sensor in spiked drinking water revealed a good recovery (95–105 %).