Electrochemical Myoglobin Biosensor Based on Magnesium Metal-Organic Frameworks and Gold Nanoparticles Composite Modified Electrode

A carbon ionic liquid electrode (CILE) made with 1-hexylpyridinium hexafluorophosphate was used as the substrate electrode. The magnesium metal-organic framework (Mg-MOF-74) was casted on CILE surface and gold nanoparticles (AuNPs) was further assembled on electrode through electrodeposition to construct a nanocomposite interface. Myoglobin (Mb) was further modified on AuNPs/Mg-MOF-74/CILE and Nafion film was used to get the working electrode (Nafion/Mb/AuNPs/Mg-MOF-74/CILE). Morphology of the nanoparticles was recorded by SEM. UV-Vis and FT-IR spectroscopy proved that Mb on the composite film retained its original structure. The Mb on AuNPs/Mg-MOF-74/CILE displayed a pair of redox peaks with the formal peak potential of -0.158 V (vs. Ag/AgCl) in 0.1 mol/L pH 2.0 PBS. Mb remained the bioactivity and electrocatalyzed the reduction of trichloroacetic acid and sodium nitrite with relative wide concentration range and low detection limit. The fabricated electrochemical biosensor gave high stability and reproducibility, which extended the application of MOF based composite in electroanalysis.