Electrochemical Sensing of Quinoline and Pyridine Utilizing Reusable Graphene-Zirconium Metal-Organic Framework Hybrids on Glassy Carbon Electrodes

Abstract The incorporation of metal–organic frameworks (MOFs) on carbon-based materials and their use as sensors for electrochemical sensing has attracted great interest. In this work, a zirconium-based functional metal–organic framework (MOF), (Zr-MOF) was deposited unto graphene aerosol (GA) and amine functionalized graphene oxide (GO) to form Zr-MOF-GA and Zr-MOF-GO hybrids, respectively, and used as electrode materials for the determination of pyridine and quinoline in model fuel. Owing to the large effective surface area of GCE compared to Zr-MOF-GA and Zr-MOF-GO, LOD values of 0.00016 wt% and 0.00032 wt% were obtained for pyridine and quinoline, respectively compared to surface areas obtained for modified electrodes Zr-MOF-GA/GCE (0.00145 wt% (pyridine) and 0.0044 wt% (quinoline)) and Zr-MOF-GO/GCE (0.00140 wt% (pyridine) and 0.00207 wt% (quinoline)). Zr-MOF-GO/GCE presented better reusability with linear range from 0.0001 to 0.0083 wt% with a sensitivity of 1.43 × 10 − 4 µA wt% −1 cm − 2 (pyridine) and 8.57 × 10 − 5 µA wt% −1 cm − 2 (quinoline). The electrode (Zr-MOF-GA and Zr-MOF-GO) also presented anti-interference to other nitrogen containing compounds and could be reused five times with a ~ 5–18% decrease of sensing signal (pyridine and quinoline). The sensor design shows promise in the development of basic nitrogen-containing compounds electrochemical sensors.