A ascorbic acid-imprinted poly(o-phenylenediamine)/zeolite imidazole frameworks-67/carbon cloth for electrochemical sensing ascorbic acid

A flexible ascorbic acid (AA)-imprinted poly(o-phenylenediamine) (ploy(o-PD))/zeolite imidazole frameworks-67 (ZIF-67)/carbon cloth (CC) electrode was prepared for electrochemical sensing AA. The flexible AA-imprinted poly(o-PD)/ZIF-67/CC electrode was prepared by growing ZIF-67 on flexible CC, electropolymerization of o-PD with AA on ZIF-67/CC and eluting template molecules AA. The results showed that the spherical ZIF-67 crystals were arranged evenly and firmly on the fibers of CC surface. The diameter of spherical ZIF-67 crystals was approximately 500–600 nm, and the spherical ZIF-67 crystals catalyzed the oxidation of AA well. A layer of poly(o-PD) with AA-imprinted pores was covered on the ZIF-67/CC electrode, so the AA-imprinted poly(o-PD)/ZIF-67/CC electrode exhibited better selectivity toward AA detection and good stability. The molecularly imprinted sensor exhibits high sensitivity, and the sensitivity could reach 959.9 μA/mM⁻¹ cm⁻², the detection limit was 0.019 μM, and the concentration range of AA was 0.057 μM–11.4 0 mM. The AA-imprinted poly(o-PD)/ZIF-67/CC electrode also showed higher stability and repeatability. The results proved that the spherical ZIF-67 crystals were good electrode materials for electrochemical AA biosensors.