Enhanced Ceftriaxone Determination using a Glassy Carbon Electrode Modified with a Cr-based Metal-Organic Framework Film Stabilized by β-Cyclodextrin Polymer

A selective amperometric sensor was developed to detect the antibiotic ceftriaxone (CEF) using a composite film of poly(beta-cyclodextrin) and a metal-organic framework (MOF). The sensor was obtained by electro-polymerizing beta-cyclodextrin (beta-CD) onto a glassy carbon electrode (GCE) previously coated with a MIL-101(Cr) MOF film. This design prevents MOF particles' loss during extended electrode use. The MOF was structurally characterized using scanning electron microscopy, X-ray diffraction, N-2 adsorption-desorption isotherms (BET method) and FTIR spectroscopy. Electrochemical impedance spectroscopy and cyclic voltammetry were used to assess the GCE/MIL-101(Cr)-p beta-CD sensor, revealing reduced charge transfer resistance and enhanced sensitivity to CEF. Differential pulse voltammetry was then employed for CEF determination. Under optimized conditions, the sensor exhibited high sensitivity, a broad linear working range of 0.5 to 6 mu M (R-2=0.991), and a low detection limit of 0.34 +/- 0.02 mu M (0.19 +/- 0.01 mg L-1). The selectivity of the sensor was evaluated in the presence of potential interferences such as organic acids, antibiotics and selected ions expected to affect the CEF signal. In an application to quantify a pharmaceutical formulation, the sensor displayed an impressive recovery rate of 98.3 % compared to results obtained using high-performance liquid chromatography.