title: Highly sensitive determination of atropine using cobalt oxide nanostructures: Influence of functional groups on the signal sensitivity.
abstract: This study describes sensitive determination of atropine using glassy carbon electrodes (GCE) modified with Co3O4nanostructures. The as-synthesised nanostructures were grown using cysteine (CYS), glutathione (GSH) and histidine (HYS) as effective templates under hydrothermal action. The obtained morphologies revealed interesting structural features, including both cavity-based and flower-shaped structures. The as-synthesised morphologies were noted to actively participate in electro-catalysis of atropine (AT) drug where GSH-assisted structures exhibited the best signal response in terms of current density and over-potential value. The study also discusses the influence of functional groups on the signal sensitivity of atropine electro-oxidation. The functionalisation was carried with the amino acids originally used as effective templates for the growth of Co3O4nanostructures. The highest increment was obtained when GSH was used as the surface functionalising agent. The GSH-functionalised Co3O4-modified electrode was utilised for the electro-chemical sensing of AT in a concentration range of 0.01-0.46 μM. The developed sensor exhibited excellent working linearity (R2= 0.999) and signal sensitivity up to 0.001 μM of AT. The noted high sensitivity of the sensor is associated with the synergy of superb surface architectures and favourable interaction facilitating the electron transfer kinetics for the electro-catalytic oxidation of AT. Significantly, the developed sensor demonstrated excellent working capability when used for AT detection in human urine samples with strong anti-interference potential against common co-existing species, such as glucose, fructose, cysteine, uric acid, dopamine and ascorbic acid.
authors.affiliation: Interface Analysis Centre, School of Physics, University of Bristol, Bristol, BS8 1TL, UK; National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, Pakistan. Electronic address: raziumsoomro@gmail.com.
authors.forename: Razium Ali
authors.initials: RA
authors.lastname: Soomro
authors.affiliation: Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia; Department of Chemistry, Faculty of Science, Sohag University, Sohag, Egypt.
authors.forename: Ayman
authors.initials: A
authors.lastname: Nafady
authors.affiliation: Interface Analysis Centre, School of Physics, University of Bristol, Bristol, BS8 1TL, UK.
authors.forename: Keith Richard
authors.initials: KR
authors.lastname: Hallam
authors.affiliation: National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, Pakistan.
authors.forename: Sana
authors.initials: S
authors.lastname: Jawaid
authors.affiliation: Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Abdullah
authors.initials: A
authors.lastname: Al Enizi
authors.affiliation: National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, Pakistan.
authors.forename: Syed Tufail Hussain
authors.initials: ST
authors.lastname: Sherazi
authors.affiliation: National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080, Pakistan.
authors.lastname: Sirajuddin
authors.affiliation: Dr M.A. Kazi Institute of Chemistry, University of Sindh, Jamshoro, 76080, Pakistan.
authors.forename: Zafar Hussain
authors.initials: ZH
authors.lastname: Ibupoto
authors.affiliation: Department of Science and Technology, Campus Norrkoping, Linkoping University, SE-60174, Norrkoping, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Willander
mesh_terms: D001285:Atropine / Q000032:analysis* / Q000652:urine; D015374:Biosensing Techniques; D003035:Cobalt / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D005978:Glutathione / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D010087:Oxides; D003035:Cobalt; D001285:Atropine; D005978:Glutathione; C060728:cobalt oxide
keywords: Amino acids; Atropine; Co(3)O(4) nanostructures; Functionalised nanomaterial