An Ascorbic Acid-Imprinted Poly(o-phenylenediamine)/AuNPs@COFTFPB-NBPDA for Electrochemical Sensing Ascorbic Acid

An electrochemical sensor based on a molecularly imprinted polymer membrane (MIP) was developed. The electrochemical sensor was prepared by electropolymerization of o-phenylenediamine (O-PD) on the surface of glassy carbon electrode (GCE), modified by AuNPs@covalent organic framework (COF) microspheres with ascorbic acid (AA) as template molecule. First, ultrasmall polyvinylpyrrolidone (PVP)-coated AuNPs were prepared by a chemical reduction method. Then, 1,3,5-tri(p-formylphenyl)benzene (TFPB) and N-boc-1,4-phenylene diamine (NBPDA) underwent an ammonaldehyde condensation reaction on PVP-coated AuNPs to form AuNPs@COFTFPB-NBPDAmicrospheres. The porous spherical structure of AuNPs@ COFTFPB-NBPDAcould accelerate the mass transfer, enlarge the specific surface area, and enhance the catalytic activity of PVP-coated AuNPs. The electrochemical sensors, based on AuNPs@ COFTFPB-NBPDA/GCE and nMIPs/AuNPs@COFTFPB-NBPDA/GCE, were applied for the detection of AA, with a detection limit of 1.69 and 2.57 μM, as well as linear ranges of 5.07 to 60 mM and 7.81 to 60 mM. The nMIPs/AuNPs@COFTFPB-NBPDAsensor had satisfactory stability, selectivity, and reproducibility for AA detection.Keywords:covalent organic framework;ascorbic acid;molecularly imprinted polymer;electrochemical sensor