Cobalt-based metal-organic framework-functionalized graphene oxide modified electrode as a new electrochemical sensing platform for detection of free chlorine in aqueous solution

Somayeh Jafari; Seied Mahdi Pourmortazavi; Ali Ehsani; Somayeh Mirsadeghi

doi:10.1016/j.ab.2023.115334

Cobalt-based metal-organic framework-functionalized graphene oxide modified electrode as a new electrochemical sensing platform for detection of free chlorine in aqueous solution

Anal Biochem. 2023 Nov 15:681:115334. doi: 10.1016/j.ab.2023.115334. Epub 2023 Sep 28.

Authors

Somayeh Jafari¹, Seied Mahdi Pourmortazavi², Ali Ehsani³, Somayeh Mirsadeghi⁴

Affiliations

¹ Faculty of Chemistry and Chemical Engineering, Malek Ashtar University of Technology, Tehran, Iran. Electronic address: somayejafari2010@yahoo.com.
² Faculty of Chemistry and Chemical Engineering, Malek Ashtar University of Technology, Tehran, Iran. Electronic address: pourmortazavi@mut.ir.
³ Department of Chemistry, Faculty of Science, University of Qom, Qom, Iran. Electronic address: a.ehsani@qom.ac.ir.
⁴ KonadHerbs Co., Sharif Innovation Area, Sharif University of Technology, Tehran, Iran. Electronic address: sshmirsadeghi@sina.tums.ac.ir.

PMID: 37774996
DOI: 10.1016/j.ab.2023.115334

Abstract

This work reports the profit of using a MOF compound for developing a sensitive electrochemical sensor to free chlorine detection in an aqueous solution. Co-MOF and FGO composites were synthesized and combined with the carbon paste (CP) to prepare an efficient electrochemical sensor with high sensing ability. The fabricated Co-MOF and FGO composites were characterized by SEM, EDX, FT-IR, and XRD techniques. Meanwhile, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were utilized to assess the electrochemical performance of the Co-MOF-FGO/CP modified electrode. Under the optimized condition, the amperometric detection showed that the reduction current of free chlorine increased linearly with a coefficient determination of 0.995 during its wide concentration range of 0.1-700 ppm. Also the detection limit (LOD) (S/N = 3) was 0.01 ppm. The selectivity of the sensor was tested with possible interferences, and satisfactory results were obtained. The proposed sensor was successfully used to determine the free chlorine in tap water and swimming pool water real samples. The results suggested that this proposed sensor could pave the way for developing the electrochemical sensor of free chlorine in aqueous media with MOFs.

Keywords: Amperometric detection; Co-MOF; Electrochemical sensing; Free chlorine; Functionalized graphene oxide; Water.