Bimetallic copper-cobalt MOFs anchored carbon nanofibers hybrid mat based electrode for simultaneous determination of dopamine and tyramine

Abstract

Early monitoring of histamine and tyramine levels in foodstuffs could protect against several diseases. In the present study, a self-standing copper-cobalt(2-methylimidazole) MOF anchored carbon nanofiber hybrid mat (Cu-Co(2-Meim)MOF@CNF) was prepared for the simultaneous detection and quantification of dopamine and tyramine in cheese and banana samples. As-prepared Cu-Co(2-Meim)MOF@CNF hybrid mats are highly porous with a large surface area, and also possess excellent hydrophilicity, which allows the analyte molecules to easily access the redox-active metal sites of the MOF matrix and subsequently enhance the sensitivity. The functional groups within the MOF matrix can also function as active adsorption sites during electrocatalysis. At the acidic condition (pH = 5.0), the Cu-Co(2-Meim)MOF@CNF exhibited improved catalytic activity and strong electrochemical sensitivity toward dopamine (DA) and tyramine (TY) with faster electron transfer kinetics and significant fouling resistance. The oxidation reactions of dopamine and tyramine at the hybrid electrode were irreversible and diffusion-controlled. The Cu-Co(2-Meim)MOF@CNF/GCE sensor demonstrated a broad linear range from 5 to 800 µM along with a low LOD of 44.2 nM and 52.7 nM for dopamine and tyramine, respectively. The hybrid sensor exhibited excellent anti-interference properties and long-term storage stability for up to 30 days. It is noteworthy that the Cu-Co(2-Meim)MOF@CNF/GCE sensor has demonstrated the capability of detecting dopamine and tyramine in cheese and banana samples, respectively, which would be helpful for food analysis and food safety.