TiO2 aerogel − A sensing electrode matrix for the sensitive detection of diclofenac sodium

• TiO 2 aerogel (AG)&bioengineered flagellin (bioF) − used for electrode preparation. • Morphostructural investigations proved that TiO 2 AG has a mesoporous structure. • The SWV technique showed a LOD of 17 nM for diclofenac sodium (DS) detection. • bioF + TiO 2 AG + Ch/GCE − stable, sensitive, and reproducible for DS detection. • The proposed electrode was used to estimate DS in wastewater and tablet samples. This study developed a new composite matrix containing TiO 2 aerogel having mesoporous structure (TiO 2 AG), bioengineered flagellin (bioF) and chitosan (Ch) deposited on a glassy carbon electrode (GCE), for the detection of diclofenac sodium (DS) in aqueous solutions. It is worth mentioning that TiO 2 AG mesoporous material was used for the first time as a sensitive matrix for DS detection. The morpho-structural properties of the new electrode materials were assessed by X-ray diffraction (XRD), N 2 adsorption–desorption measurements, and scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy. The electrochemical properties of the new bioF + TiO 2 AG + Ch/GCE modified electrode were determined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV) techniques. The developed modified electrode exhibits a significant electrocatalytic activity for DS electrooxidation process reflected in the acquired performances (detection limit of 17 nM, sensitivity of 0.41 A/M, linear range from 0.15 to 2.5 µM), and presents excellent reproducibility, repeatability, and stability. The practical use of the new developed electrode was estimated by quantifying DS in pharmaceutical formulations (recovery mean of 100.66 % for DS, with a relative standard deviation of 0.39 %) and wastewater samples (relative error of 3.15 % and a relative standard deviation of 0.393 when compared to the LC-MS standard technique).