A novel electrochemical sensor based on PVP–Co(OH)2 nanocomposite for the sensitive detection of Cu(II) ions

Herein, a nanocomposite comprising polyvinyl pyrrolidone (PVP) and cobalt(II) hydroxide (Co(OH)2) nanoparticles (PVP–Co(OH)2) was synthesized via a hydrothermal method and used for detection of Cu(II) ions. Using PVP grafted nanosized Co(OH)2 as a surfactant could decrease the aggregation and reduce the particle size. The conducted morphology investigations showed that PVP–Co(OH)2 nanocomposite was composed of small spherical particles with a diameter of 40–80 nm that could accelerate mass diffusion and favor the deposition-stripping process of Cu(II) ions. High catalytic activity of Co(OH)2 and good affinity of PVP to Cu(II) ions synergistically enhances sensing performance of the PVP–Co(OH)2 nanocomposite-modified electrode than Co(OH)2- and PVP-modified electrodes. A linear response was obtained for Cu(II) ion concentration over a range of 1.0–90.0 μg/L, with a detection limit of 0.26 μg/L (S/N = 3). The proposed electrode exhibited good performance in terms of selectivity, stability, and reproducibility. It was also employed to detect Cu(II) ions in water and food samples, and the results were in good agreement with those obtained by graphite furnace atomic absorption spectrometry.