Sol–gel thin-film based mesoporous silica and carbon nanotubes for the determination of dopamine, uric acid and paracetamol in urine

• Published in: Talanta (Oxford) Vol. 116; pp. 726 - 735
• Main Authors: Canevari, Thiago C., Raymundo-Pereira, Paulo A., Landers, Richard, Benvenutti, Edilson V, Machado, Sérgio A.S.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.11.2013
• Subjects: acetaminophen; Acetaminophen - urine; Carbon nanotubes; catalysts; detection limit; Dopamine; Dopamine - urine; Electrochemical sensor; Electrochemical Techniques; Electrodes; Glassy carbon; glassy carbon electrode; Humans; Hydrofluoric Acid - chemistry; Hydrogen-Ion Concentration; Limit of Detection; Mesoporous silica; Microscopy, Electron, Scanning; Nanotubes, Carbon - chemistry; Nanotubes, Carbon - ultrastructure; nitrogen; Oxidation; Oxidation-Reduction; Paracetamol; Phase Transition; phosphates; Porosity; Raman spectroscopy; scanning electron microscopy; silica; Silicon dioxide; Silicon Dioxide - chemistry; Sol gel process; sol-gel processing; statistical analysis; Statistical methods; Thin films; transmission electron microscopy; Uric acid; Uric Acid - urine; urine; X-ray diffraction; X-ray photoelectron spectroscopy; Carbon nanotubes; Paracetamol; Dopamine; Uric acid; Electrochemical sensor; Mesoporous silica
• DOI: 10.1016/j.talanta.2013.07.044
• ISSN: 0039-9140

This work describes the preparation, characterization and application of a hybrid material composed of disordered mesoporous silica (SiO2) modified with multiwalled carbon nanotubes (MWCNTs), obtained by the sol–gel process using HF as the catalyst. This hybrid material was characterized by N2 adsorption–desorption isotherms, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission microscopy (HR-TEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). This new hybrid material was used for the construction of a thin film on a glassy carbon electrode. The modified electrode using this material was designated SiO2/MWCNT/GCE. The electrocatalytic properties of the electrode toward dopamine, uric acid and paracetamol oxidation were studied by differential pulse voltammetry. Well-defined and separated oxidation peaks were observed in phosphate buffer solution at pH 7.0, in contrast with the ill-defined peaks observed with unmodified glassy carbon electrodes. The electrode had high sensitivity for the determination of dopamine, uric acid and paracetamol, with the limits of detection obtained using statistical methods, at 0.014, 0.068 and 0.098µmolL−1, respectively. The electrode presented some important advantages, including enhanced physical rigidity, surface renewability by polishing and high sensitivity, allowing the simultaneous determination of these three analytes in a human urine sample. •A new silica-based hybrid material containing carbon nanotubes physically incorporated in the mesoporous silica matrix, SiO2/MWCNT, was obtained by the sol–gel process using HF as catalyst.•Good separation peaks between dopamine, uric acid and acetaminophen allowed the simultaneous determination of species.•Good electrocatalytic response regarding individual and simultaneous determination of species with a low detection limit.•Determination of these species in urine without any interference between them.