OICC Press Journal of Nanostructure in Chemistry 2193-8865 11 3 (September 2021) 2021 01 04 Functional Co3O4 nanostructure-based electrochemical sensor for direct determination of ascorbic acid in pharmaceutical samples 10.1007/s40097-020-00380-8 EN Nadir H. Khand National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, PK Ismail M. Palabiyik Department of Analytical Chemistry, Faculty of Pharmacy, Ankara University, Ankara, TR Jamil A. Buledi National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, PK Sidra Ameen National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, PK Department of Chemistry, Shaheed Benazir Bhutto University, Sindh, 67450, PK Almas F. Memon National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, PK Tania Ghumro National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, PK Amber R. Solangi National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, PK Journal Article 2021 01 04 Abstract Ionic liquid (IL)-assisted Co 3 O 4 nanostructures were synthesized by a simple, facile and novel low-temperature aqueous chemical growth method and used for the modification of glassy carbon electrode (GCE) for the selective determination of ascorbic acid (AA). Different volumes of IL were used in the preparation of nanostructures to examine the effect of IL on the morphology and electrochemical performance of the synthesized material. The functionalities of the prepared material were investigated by FTIR, while the crystalline nature and phase purity of the material were confirmed by XRD results. FESEM analysis were carried out to expose the surface characteristics of the prepared nanostructures and the results demonstrated that the cobalt oxide nanostructures possess nanorods like morphology. The EDX results verified the maximum elemental percent composition for the cobalt and oxygen in the synthesized material. The electrochemical performance of Co 3 O 4 nanostructures modified GCE was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical results demonstrated that the modified electrode shown outstanding performance in the determination of AA with a very low limit of detection (1 µM) along with higher stability and repeatability features. The novel AA sensor manifested exceptional sensitivity and selectivity over a wide linear range of concentration from 0.05 to 3 mM with the coefficient of determination R 2  = 0.998. The applicability of the developed sensor was examined in the pharmaceutical samples that contain AA and the sensor selectively detected the AA from multiple ingredients that were present in their formulation with acceptable recovery. Graphic abstract It describes the synthesis of [BMIM][PF 6 ] IL functionalized cobalt oxide nanostructures through low-temperature aqueous chemical growth method and the synthesized material was utilized to fabricate an electrochemical sensor (Co 3 O 4 /GCE) for the selective determination of Ascorbic acid.