Modification of Recycled Graphite Electrode by Cobalt-Iron Nanoarchitectonic with β-Cyclodextrin for Furosemide Detection in Natural Teas and Slimming Food Supplements

Employing nanoarchitectonics and a host−guest strategy, this work develops a novel sustainable electrochemical sensor to detect furosemide (FUR) in slimming health foods. A recycled graphite electrode (GrCE) from spent Zn-C batteries was modified with a Co3[Co(CN)6]2/Fe3O4-β-cyclodextrin(CD) nanocomposite, leveraging supramolecular interactions to enhance FUR affinity and detection. Therefore, the research connects circular economy principles for application in global food security. The Co3[Co(CN)6]2/Fe3O4-CD nanoarchitectonic formed via chemical precipitation increased the GrCE electroactive surface area, enabling FUR detection through voltammetric current inhibition. Thus, the current inhibition mechanism was employed to detect FUR using linear sweep voltammetry (LSV). The LSV response of Co3[Co(CN)6]2/Fe3O4-CD|GrCE in the presence of FUR exhibited a linear working range from 0.04 to 4.25 μmol L−1, excellent sensitivity of 4.53 mA μmol−1 L cm−2, and low limit of detection of 6.02 nmol L−1. Moreover, the developed approach exhibits high specificity, storage stability, and good precision. The tests in aqueous solutions containing teas and slimming capsules showed satisfactory recovery levels of their respective concentrations, varying from 97.57 to 102.4% and 96.86 to 104.8%, respectively. The electrochemical sensor developed in this study shows potential for the detection and monitoring of FUR in dietary food supplements, offering sensitivity and cost-effectiveness.