Efficient detection of metronidazole by a glassy carbon electrode modified with a composite of a cyclotriveratrylene-based metal–organic framework and multi-walled carbon nanotubes.

A new cyclotriveratrylene-based metal–organic framework 1 was combined with multi-walled carbon nanotubes to give a conductive 1@MWCNT sensor, which featured efficient detection of metronidazole. [Display omitted] • A new metal–organic framework [Cd 6 L 2 (cyclen) 2 (H 2 O) 2 ] (1) was designed. • 1 was dispersed in multi-walled carbon nanotubes to give conductive 1@MWCNT. • 1@MWCNT featured intense electrocatalytic activity for metronidazole detection. • The synergistic effect between 1 and MWCNT enhanced the sensing performances. Constructing a sensitive and efficient sensor for determination of metronidazole (MNZ) is crucial in food field. Herein, a new cyclotriveratrylene-based metal–organic framework (MOF), namely, [Cd 6 L 2 (cyclen) 2 (H 2 O) 2 ] (1), was constructed by self-assembly of functionalized 5,6,12,13,19,20-hexacarboxy-propoxy-cyclotriveratrylene (H 6 L), 1,4,7,10-tetraazacyclododecane (cyclen) and Cd(II) cation under solvothermal condition. In 1 , adjacent Cd(II) cations are linked by L6− to produce a 2D polymeric structure with carboxylate and phenolic oxygen atoms. To enhance conductivity of 1 , it was combined with conducting carbon materials, including mesoporous carbon (MC), reduced graphene oxide (RGO) and multi-walled carbon nanotubes (MWCNT), respectively, producing a series of composite materials. Remarkably, electrochemical tests showed that 1 @MWCNT(1:1) featured a much better electrochemical detection performance for metronidazole (MNZ) than 1 @MC and 1 @RGO. The linear range for the detection of MNZ is up to 0.4–500 μM and the limit of detection (LOD) for MNZ reached 0.25 μM. Importantly, the fabricated sensor 1 @MWCNT(1:1) was employed for the detection of MNZ in honey and egg with satisfactory result. High-performance liquid chromatography (HPLC) validated the high accuracy of the electrochemical method for the determination of honey and egg. [ABSTRACT FROM AUTHOR]