DUT-67 and tubular polypyrrole formed a cross-linked network for electrochemical detection of nitrofurazone and ornidazole.

The cross-linked network of DUT-67/tubular polypyrrole (T-PPY) composites was first synthesized by in-situ growth zirconium - based metal-organic frameworks (DUT-67) with T-PPY. The introduction of T-PPY effectively increases conductivity of DUT-67/T-PPY composites, weakens accumulation of the DUT-67, and exposes more active sites of DUT-67. DUT-67/T-PPY/GCE manifests increased electrocatalytic activity toward reduction of nitrofurazone and ornidazole compared with DTU-67. A novel electrochemical sensor based on DUT-67/T-PPY was established to effectively detect two anti-infective drugs, respectively. Under optimized experimental conditions, the proposed sensor shows a wider linear range for nitrofurazone that is composed by two line segments (9.08-354.08 μM and 354.08-1004.04 μM). Meanwhile, the sensor also displays a linear response to ornidazole in the range of (0.7-100.5 μM and 100.5-250.4 μM) as well as a low LOD as 0.25 μM (S/N = 3). The proposed sensor was used for the detection of nitrofurazone and ornidazole in actual samples, and the satisfactory results were acquired. This research provides an efficient strategy for fabricating novel electrochemical sensor based on cross-linked network structure of T-PPY and MOFs.