Potentiometric Zinc Ion Sensor Based on Honeycomb-Like NiO Nanostructures

Mazhar Abbasi,Omer Nur,Mushtaque Hussain,Yaqoob Khan,Azam Khan,Zafar Ibupoto,Magnus Willander

doi:10.3390/s121115424

Abstract

In this study honeycomb-like NiO nanostructures were grown on nickel foam by a simple hydrothermal growth method. The NiO nanostructures were characterized by field emission electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) techniques. The characterized NiO nanostructures were uniform, dense and polycrystalline in the crystal phase. In addition to this, the NiO nanostructures were used in the development of a zinc ion sensor electrode by functionalization with the highly selective zinc ion ionophore 12-crown-4. The developed zinc ion sensor electrode has shown a good linear potentiometric response for a wide range of zinc ion concentrations, ranging from 0.001 mM to 100 mM, with sensitivity of 36 mV/decade. The detection limit of the present zinc ion sensor was found to be 0.0005 mM and it also displays a fast response time of less than 10 s. The proposed zinc ion sensor electrode has also shown good reproducibility, repeatability, storage stability and selectivity. The zinc ion sensor based on the functionalized NiO nanostructures was also used as indicator electrode in potentiometric titrations and it has demonstrated an acceptable stoichiometric relationship for the determination of zinc ion in unknown samples. The NiO nanostructures-based zinc ion sensor has potential for analysing zinc ion in various industrial, clinical and other real samples.

Highlights

Zinc ion is the most abundant heavy metal ion in the human body and the quantity of zinc ion in serum is around 10 μM
Many analytical techniques has been used for the determination of zinc ion, including UV-Vis spectroscopy [15], potentiometry [16] and flame atomic absorption spectrometry [17], inductively coupled plasma atomic emission spectrometry (ICPAES) [18] and fluorescence methods [19,20]
N nanostrructures weere clearly seen s at highh field emission electron microscopy (FESEM) m magnification and from m thhis it can bee seen that the t grown nickel oxide (NiO)

Summary

Introduction

Zinc ion is the most abundant heavy metal ion in the human body and the quantity of zinc ion in serum is around 10 μM. Many analytical techniques has been used for the determination of zinc ion, including UV-Vis spectroscopy [15], potentiometry [16] and flame atomic absorption spectrometry [17], inductively coupled plasma atomic emission spectrometry (ICPAES) [18] and fluorescence methods [19,20]. These techniques have some limitations due to the completely filled d-orbital of zinc ion, which results in an absence of suitable spectroscopic or magnetic signals. A Schiff's base has been used for the detection of zinc ion [33]

Methods

Results

Conclusion