Ultrasensitive colorimetric detection of Hg²⁺ in aqueous media via green synthesis by Ziziphus mauritiana Leaf extract-based silver nanoparticles

Abstract

This study is based on green, efficient and simple synthesis of silver nanoparticles from Ziziphus mauritiana (Zm) leaves extract as capping and reducing agent. Initially synthesised silver nanoparticles were characterised by using UV-Visible spectrophotometer and FT-IR to examine the functional change that occurs before and after synthesis. Furthermore atomic force microscopy (AFM) was used to investigate the average size of Zm-AgNPs 7–22 nm, while scanning electron microscopy (SEM) revealed the shape of synthesised Zm-AgNPs. Shape and size of nanoparticles were also confirmed by transmission electron microscopy (TEM). The Zm-AgNPs has been successfully applied for colorimetric detection of mercury from aqueous media with concentration range of 3–23 nM based on decrease and shift in LSPR band intensity and method shows good regression co-efficient R² = 0.987 with low limit of detection (LOD) 0.04 nM and limit of quantification, 1.5 nM. The developed colorimetric sensor exhibits outstanding properties for Hg²⁺ detection and worked as highly stable and selective, greener with cheaper and easy way of detection. On the other hand, the method was successfully applied in various type of real water sample.

KEYWORDS:

• Ziziphus mauritiana. L
• silver nanoparticles
• green synthesis
• colorimetric sensor
• mercuric ion
• real water samples

Acknowledgments

We highly acknowledge the Higher Education Commission, Islamabad and the National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan for facilities during this research.

Disclosure statement

The authors have no conflict of interest to declare.