In-situ grown hexagonal rod-like ZIF-L(Zn/Co) variant on reduced graphene oxide (rGO) for the enhanced electrochemical sensing of acetaminophen

Abstract

Graphene – one of the most regarded materials in the world of Flatland has a substantial role in sensing applications due to its exceptional properties. Combining graphene with MOF can effectively mitigate the limitations of MOF while synergistically enhancing their unique properties. In this research work, we present a new hybrid composite of Zeolite Imidazolate Framework-L made composite with reduced graphene oxide, ZIF-L(Zn/Co)/rGO (ZLG) and applied its electrocatalytic performance in the sensitive detection of acetaminophen (AP). The mixture was prepared via a simple in-situ solvothermal method whose physico-chemical nature was investigated in detail. The ZIF-L phase identification, morphological change of ZIF, confirmation of rGO incorporation, and chemical composition analysis were established using the XRD, SEM, Raman and XPS respectively. Additionally, the kinetics of electron transfer was studied by EIS. Thereafter, proper optimization of various sensor parameters such as pH, scan rate and analytical performance were executed. Preliminary sensing studies carried out by cyclic voltammetry revealed an enhancement in peak current from 0.48µA to 1.05µA upon incorporation of rGO into the ZIF-L(Zn/Co) hybrid. Compared with reported studies along a similar vein, from the differential voltammetric analysis the ZLG-modified GCE displays a high selectivity towards AP with a broad linear range of 1 µM – 2060 µM exhibiting a sensitivity and LOD of 8.145 µA/mM and 162 nM respectively. The real-time validation of the sensor in paracetamol tablets and biological samples of human blood and urine exhibited recovery values in the range of ∼ 94 % − 102 %. Hence, this suggests a reliable practical applicability of the sensor owing to the high catalytic, large surface area and increased conductivity of the nanocomposite.