Ultrasensitive Platform for Electrochemical Sensing of Copper and Antimony Based on Poly(1,5-Diaminoanthraquinone)/Multiwalled Carbon Nanotubes/Carbon Paste Electrode

A new sensor for the detection of copper (II) (Cu2+) and antimony (III) (Sb3+) metal ions is described herein. The sensor is based on multi-walled carbon nanotubes mixed with a carbon paste electrode modified by poly(1,5-diaminoanthraquinone) (p-1,5-DAAQ). The Cu(2+)and Sb(3+)ions were effectively detected by square wave anodic stripping voltammetry (SWASV) both individually and simultaneously. The proposed modified electrode was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Poly(1,5-diaminoanthraquinone)/multi-walled carbon nanotubes/carbon paste electrode (p-1,5-DAAQ/MWCNT/CPE) was utilized for electrochemical determination of Cu(2+)and Sb(3+)under pre-optimized conditions (i.e., deposition potential, deposition time, square wave frequency, and concentration of HCl). For simultaneous detection, a linear range of 1-180 mu l(-1)was employed with a limit of determination (LOD) of 1.3 and 1.4 ng l(-1)for Cu(2+)and Sb3+, respectively. Moreover, for individual detection, a linear range of 2-30 mu g l(-1)was used for Sb3+, while for Cu(2+)it was set at 0.5-25 mu g l(-1), with a limit of detection of 205.7 ng l(-1)and 1.9 ng l(-1)for Cu(2+)and Sb3+, respectively. The effects of Tween 80 (nonionic surfactant) and humic acid on the metal peak current were also studied. Water samples spiked with both Cu(2+)and Sb(3+)were analyzed utilizing the proposed method as well as by inductively coupled plasma-mass spectroscopy (ICP-MS). Overall, good recovery values were achieved, demonstrating the applicability of the described approach for the detection of metal ions in real water samples.