Application of synthesized copper nanoparticles using aqueous extract of Ziziphus mauritiana L. leaves as a colorimetric sensor for the detection of Ag

The presented work demonstrates the preparation of copper nanoparticles (CuNPs) via aqueous leaves extract of Ziziphus mauritiana L. (Zm) using hydrazine as a reducing agent. Various parameters such as volume of extract, concentration of hydrazine hydrate, concentration of copper chloride, and pH of the solution were optimized to obtain Ziziphus mauritiana L. leaves extract derived copper nanoparticles (Zm-CuNPs). Brownish red color was initial indication of the formation of Zm-CuNPs while it was confirmed by surface plasmon resonance (SPR) band at wavelength of 584 nm using ultraviolet-visible (UV-vis) spectroscopy. Synthesized Zm-CuNPs were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffractometry (XRD). AFM images showed that the particle size of Zm-CuNPs was from 7 to 17 nm with an average size of 11.3 nm. Fabricated sensor (Zm-CuNPs) were used as a colorimetric sensor for the detection of Ag+ at a linear range between 0.67 × 10–6 – 9.3 × 10–6 with R2 value of 0.992. For real water samples, limit of quantification (LOQ) and limit of detection (LOD) for Ag+ was found to be 330 × 10–9 and 100 × 10–9, respectively.