A Paper-Based Electrochemical Sensor Based on PtNP/COF(TFPB−DHzDS)@rGO for Sensitive Detection of Furazolidone

Herein, a paper-based electrochemical sensor based on PtNP/COF(TFPB−DHzDS)@rGO was developed for the sensitive detection of furazolidone. A cluster-like covalent organic framework (COF(TFPB−DHzDS)) was successfully grown on the surface of amino-functional reduced graphene oxide (rGO-NH(2)) to avoid serious self-aggregation, which was further loaded with platinum nanoparticles (PtNPs) with high catalytic activity as nanozyme to obtain PtNP/COF(TFPB−DHzDS)@rGO nanocomposites. The morphology of PtNP/COF(TFPB−DHzDS)@rGO nanocomposites was characterized, and the results showed that the smooth rGO surface became extremely rough after the modification of COF(TFPB−DHzDS). Meanwhile, ultra-small PtNPs with sizes of around 1 nm were precisely anchored on COF(TFPB−DHzDS) to maintain their excellent catalytic activity. The conventional electrodes were used to detect furazolidone and showed a detection limit as low as 5 nM and a linear range from 15 nM to 110 μM. In contrast, the detection limit for the paper-based electrode was 0.23 μM, and the linear range was 0.69–110 μM. The results showed that the paper-based electrode can be used to detect furazolidone. This sensor is a potential candidate for the detection of furazolidone residue in human serum and fish samples.