Highly Efficient Functionalized Chitosan in the Development of Electrochemical Sensor for Trace Detection of Pb (II)

Abstract

Fabrication of a working electrode with silane grafted chitosan (CHTMS) employed in the sensitive detection of Pb(II) in aqueous media is presented. Several advanced analytical methods have extensively characterized the nanocomposite material. The prepared material was subsequently employed for modification of a glassy carbon electrode (GCE) and characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which show a 3-fold enhancement in surface area compared with the bare GCE, and a charge transfer resistance of 678.7 Ω. The modified electrode was employed in the sensitive determination of Pb(II) in aqueous media using differential pulse anodic stripping voltammetry (DPASV), where optimization of experimental parameters such as pH, deposition time, and deposition potential was carried out. Under optimized conditions, the linear regression and correlation coefficient were obtained, which show that Pb(II) can be detected over a wide concentration range with a calculated limit of detection (LOD) of 3.47 µg/L, which is lower than the permissible limit set by the WHO. For practical applicability, reproducibility and stability tests, as well as real water sample analyses were further performed, with the obtained recovery rates showing promising results.

Greener synthesis of novel nanocomposite material for efficient and selective trace detection of Pb²⁺: Insights of stability and real implications of fabricated electrode

“…Synthesis: Silane grafted chitosan (ChS) and Ag(NPs) decorated ChS A facile sol-gel process was used to prepare silane-grafted chitosan (ChS). The detailed procedure is included elsewhere [30]. The Ag(NPs) were decorated with the ChS (3-trimethoxyoctylsilane grafted chitosan) composite material by in situ process.…”

“…The GC electrode surface was drop casted with 0.02 mL of Ag(NPs)/ChS suspension (10 mg Ag(NPs)/ChS + 10 mL of deionized water), which was then dried for 30.0 minutes at 40°C in the oven. The electrode was kept at room temperature for cooling before being submerged for 5.0 minutes in the 0.1% glutaraldehyde solution to facilitate the crosslinking of nanocomposite material [30].…”

“…The results showed that the fabricated electrode possessed an enhanced electrochemical response for the Pb 2+ in aqueous medium. The high value of peak current is due to the abundance of -NH 2 and siloxane sites in the nanocomposite material, which facilitate the preferential chelation of lead ions at the electrode surface and cause of higher oxidative peak current using the fabricated electrode [30]. Additionally, the free energy charge due to Ag 0 decoration on the surface of electrode further catalyses the electron transfer rate at the interface of electrode resulting in high oxidative peak current [45].…”

“…Additionally, the free energy charge due to Ag 0 decoration on the surface of electrode further catalyses the electron transfer rate at the interface of electrode resulting in high oxidative peak current [45]. Previously it was reported that using the silane grafted chitosan (CHTMS) composite caused an increase in oxidative peak current Pb 2+ due to available siloxane site within the chitosan matrix [30]. Moreover, using the Ag(NP)/ChS/GC, the oxidative peak current is increased by almost 3 fold compared to the previously reported CHTMS/GC and Ca.…”

“…Chitosan, a natural biopolymer possesses excellent physical properties viz., high film forming capacity, strong adhesion, high permeability, and non-toxicity, make it ideal for a number of applications, including sensor development. Moreover, swelling and hydrophilic nature of chitosan enhances electron transfer processes in the sensor applications [14,15]. Furthermore, literature review showed that the physical and chemical properties of chitosan is easily altered due to the presence of amino and hydroxyl group in their polymeric chain, which further improves the applicability of chitosan in various applications [16].…”