Hydroxyapatite Nano-Rods/Chitosan Modified Glassy Carbon Electrode for Cu(II) Ions Determination

In this work, we propose a simple approach for fabrication of an electrochemical sensor for copper (II) ion determination in aqueous solution based on using a hydroxyapatite nano-rods/chitosan (HA/CS) nanocomposite coated on glassy carbon electrode (GCE) surface. Firstly, hydroxyapatite (HA) nano-rods has been synthesized by a simple precipitation reactions using Ca(OH) 2 slurry and orthophosphoric acid (H 3 PO 4 ) as precursors. After that, as-synthesized HA was dispersed into chitosan (CS) matrix to HA/CS-modify GCE by a drop casting technique. Characteristic of HA and HA/CS coating on GCE have been analysed by Transmission/Scanning Electron Microscope (TEM/SEM), X-ray Diffraction (XRD) and Fourier-Transform infrared spectroscopy (FT-IR) techniques. Electrochemical activities of neat GCE, CS-modified GCEs (GCE/CS) and HA/CS-modified GCE (GCE/HA/CS) have been evaluated in sodium acetate (NaAc-HAc) buffer with presence/absence of Ni 2+ , Co 2+ or Cu 2+ ions to test whether sensitive and selective of these developed Cu 2+ sensors. Evaluated results demonstrated that GCE/HA/CS sensor has a sensitivity to Cu 2+ ion of 7.688 ± 0.5324 µA mM − 1 , it is the most sensitive to Cu 2+ ions compared with GCE or GCE/CS. In additional, proposed Cu 2+ electrochemical sensor has been applied to determine Cu 2+ ions concentration in tap water with a high recoveries was found. Graphic Abstract