Construction of a voltammetric sensor based on MIL-101 hollow cages for electrocatalytic oxidation and sensitive determination of nitrofurazone

Antibiotic pollution as a hot issue of global concern is extraordinarily sought after due to the deleterious consequences on ecosystems and human health from the excessive utilization and deficient management. Achieving determination of antibiotics residues in food is greatly crucial but remains challenging. In this work, a rational strategy was employed to fabricate chromium (III) terephthalate MOF (MIL-101) hierarchical hollow cages through crystal growth and subsequent acid etching processes. The material has been characterized using several characterizations such as scanning electron microscopy, transmission electron microscopy, and X-ray powder diffraction, showing the porous MIL-101 microspheres were made of large inner cavity and single-crystalline shell. An electrochemical sensor based on the hollow MIL-101 was then developed for the determination of nitrofurazone (NFZ). Electrochemical measurements indicate that the hollow MIL-101 has highly electrocatalytic activity and excellent voltammetric response towards the NFZ oxidation, exhibiting as a wide linear range of 0.030-55 mu M and a low detection limit of 10 nM (S/N = 3). Moreover, detection of NFZ in food samples was carried out by standard addition method. Acceptable result with recovery of 93.2-103% was obtained for six parallel measurements. Our work provides a promising strategy to construct electrochemical sensors with extended applicability for analysis in complex food matrices.