title: Optimization of modified carbon paste electrode with multiwalled carbon nanotube/ionic liquid/cauliflower-like gold nanostructures for simultaneous determination of ascorbic acid, dopamine and uric acid.
abstract: We describe the modification of a carbon paste electrode (CPE) with multiwalled carbon nanotubes (MWCNTs) and an ionic liquid (IL). Electrochemical studies by using a D-optimal mixture design in Design-Expert software revealed an optimized composition of 60% graphite, 14.2% paraffin, 10.8% MWCNT and 15% IL. The optimal modified CPE shows good electrochemical properties that are well matched with model prediction parameters. In the next step, the optimized CPE was modified with gold nanostructures by applying a double-pulse electrochemical technique. The resulting electrode was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and electrochemical impedance spectroscopy. It gives three sharp and well-separated oxidation peaks for ascorbic acid (AA), dopamine (DA), and uric acid (UA). The sensor enables simultaneous determination of AA, DA and UA with linear responses from 0.3 to 285, 0.08 to 200, and 0.1 to 450 μM, respectively, and with 120, 30 and 30 nM detection limits (at an S/N of 3). The method was successfully applied to the determination of AA, DA, and UA in spiked samples of human serum and urine.
authors.affiliation: Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 65174, Hamedan, Iran.
authors.forename: Ahmadreza
authors.initials: A
authors.lastname: Afraz
authors.affiliation: Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 65174, Hamedan, Iran. Electronic address: aa_rafati@basu.ac.ir.
authors.forename: Amir Abbas
authors.initials: AA
authors.lastname: Rafati
authors.affiliation: Department of Materials Engineering, Hamedan University of Technology (HUT), 65169 Hamedan, Iran.
authors.forename: Mojgan
authors.initials: M
authors.lastname: Najafi
mesh_terms: D001205:Ascorbic Acid / Q000097:blood / Q000652:urine; D015374:Biosensing Techniques; D058266:Dielectric Spectroscopy; D004298:Dopamine / Q000097:blood / Q000652:urine; D055664:Electrochemical Techniques; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D006801:Humans; D052578:Ionic Liquids / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010084:Oxidation-Reduction; D013052:Spectrometry, X-Ray Emission; D014527:Uric Acid / Q000097:blood / Q000652:urine; D014961:X-Ray Diffraction
chemical_list: D052578:Ionic Liquids; D037742:Nanotubes, Carbon; D014527:Uric Acid; D006046:Gold; D001205:Ascorbic Acid; D004298:Dopamine
keywords: Carbon paste electrode; Gold nanostructure; Ionic liquid; Multiwalled carbon nanotube