A stable and efficient electrochemical sensor for hydroquinone and catechol detection in real-world water samples using mesoporous CaM@rGO nanocomposite

Hydroquinone (HQ) and catechol (CC) are widespread environmental pollutants known for their high toxicity and poor biodegradability. Herein, we devised an electrochemical sensor for sensitive and selective detection of HQ and CC. The glassy carbon electrode (GCE) was meticulously modified by using the Ca-perovskite (CaTiO 3 /GCE), zinc-based metal-organic frameworks (Zn-MOF/GCE), and their nanocomposite with reduced graphene oxide (rGO), i.e., CaTiO 3 -Zn-MoF@rGO/GCE (CaM@rGO/GCE). The CaM@rGO/GCE sensor showed stupendous electrochemical performance due to the synergistic effects of rGO's high conductivity and Ca-perovskite's electrocatalytic activity. Furthermore, the Zn-MOF component ensures the sensor's remarkable stability. The developed sensor boasts impressive selectivity towards HQ and CC, achieving exceptionally low detection limits (0.0086 µM (S/N = 3) for HQ, 0.0115 µM (S/N = 3) for CC), and broad linear ranges (0.05–105 µM for HQ, 0.05–120 µM for CC). The sensor shows better sensitivity to hydroquinone (HQ) than catechol (CC) due to the absence of intramolecular hydrogen bonding in HQ. The sensor's real-world applicability was validated by analyzing environmental water samples, demonstrating its immense potential for practical environmental monitoring. • Development of stupendous CaTiO 3 -Zn-MoF@rGO/GCE electrochemical sensor. • Development of a method for improving electrocatalyst stability of the sensor. • Detection of HQ and CC with LOD of 0.0086 µM and 0.0115 µM. • In real-time sample analysis, the sensors were proven to be useful.