Determination of trace amount of iron cations using electrochemical methods at N, S doped GQD modified electrode

Abstract

In this work, nitrogen and sulfur co-doped graphene quantum dot-modified glassy carbon electrodes (N, S-GQD/GCE) were used for the recognition of iron cations in aqueous solutions. The dissolved cations are detected based on the faradaic reduction or oxidation current of Fe(III) and Fe(II) obtained at the N, S-GQD/GCE surface. Cyclic voltammetry (CV), square wave voltammetry (SWV), and hydrodynamic amperometry are used as suitable electrochemical techniques for studying electrochemical behavior and determination of Fe cations. Based on the obtained results, it is concluded that the presence of free electrons in the structure of N, S-GQD could facilitate electron transfer reaction between Fe(III) and electrode surface which with increased surface area results in increased sensitivity and lower limit of detection. By performing suitable experiments, the best condition for preparing the modified electrode and determining Fe(III) was selected. Under optimized conditions, the amperometric response is linear from 1 to 100 nM of Fe(III) with a detection limit of 0.23 nM. The validity of the method and applicability of the sensor is successfully tested by the determination of Fe(III) in drug and water real samples. This sensor opened a new platform based on doped nanoparticles for highly sensitive and selective detection of analytes.

Development of isoniazid electrochemical sensor using nickel ferrite - nitrogen and sulfur co-doped graphene quantum dot nanocomposite as a new electrode modifier

“…After synthesizing N, S:GQD as reported in previous work and in Supplementary Information (SI) 39 , 0.04 g of synthesized N, S:GQD in 20.0 mL of water was sonicated for 30 min to form a clear solution. Then slowly and under mechanical stirring, nickel ferrite (0.04 g) was added to the mixture, and the mixture was heated to 100 °C.…”

“…GQDs are usually functionalized or doped with different heteroatoms to enhance intrinsic properties and change electronic structures 26 – 31 . Doping multiple heteroatoms attracted a lot of attention because it increases the holes on the surface of quantum dots increasing their conductivity and electrochemical activity 32 – 39 . It is concluded that the problem of low electrical conductivity of ferrites can be solved by composing them with heteroatom-doped GQDs, which makes it possible to use them as electrode modifiers with improved performance and efficiency.…”

Promising porous spherical PbI2/poly-2-aminobenzenethiol nanocomposite as a photocathode for hydrogen generation from Red Sea water

“…Conjugated polymers represent a novel class of photoprotective materials with high activity against both UV and visible light. Key members of this class include polypyrrole, polyaniline and polythiophene and their derivatives [14,15]. Extensively explored and applied, these conjugated polymers have found utility as supercapacitor electrodes and in cancer cell ablation.…”