title: Comparative electrochemical study of new self-assembled monolayers of 2-{[(Z)-1-(3-furyl)methylidene]amino}-1-benzenethiol and 2-{[(2-sulfanylphenyl)imino]methyl}phenol for determination of dopamine in the presence of high concentration of ascorbic acid and uric acid.
abstract: The comparative electrochemical behavior of self-assembled monolayers of two Schiff's bases, 2-{[(Z)-1-(3-furyl)methylidene]amino}-1-benzenethiol (FMAB) and 2-{[(2-sulfanylphenyl)imino]methyl}phenol (SIMP) on a bare gold electrode (Au FMAB SAM-modified electrode and Au SIMP SAM-modified electrode, respectively), was investigated by means of cyclic voltammetry and electrochemical impedance spectroscopy in a 0.1 mol L(-1) KCl solution that contains 5.0 × 10(-3) mol L(-1) [Fe(CN)(6)](3-/4-). The results revealed that the modified electrodes showed an electrocatalytic activity toward the anodic oxidation of dopamine by a marked enhancement in the current response and lower overpotential (60 and 90 mV for the Au FMAB and Au SIMP SAM-modified electrodes, respectively) in phosphate buffer solution at pH 6.0. The Au SIMP SAM-modified electrode was applied successfully to the determination of dopamine in the presence of a high concentration of ascorbic acid. Selective detection was realized in total elimination of ascorbic acid response-a method different from the ones based on the potential separations. The detection limit of dopamine was 5.0 × 10(-8) mol L(-1) in a linear range from 1.0 × 10(-6) to 1.2 × 10(-4) mol L(-1) in the presence of 1.0 × 10(-3) mol L(-1) ascorbic acid. The interference studies also showed that the Au SIMP SAM-modified electrode exhibited good selectivity in the presence of a large excess of uric acid and could be employed for the determination of dopamine in pharmaceutical formulations, plasma samples and human urine with adequate selectivity and precision.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Kashan, Kashan, 87317-51167, I.R. Iran. m.behpour@kashanu.ac.ir
authors.forename: Mohsen
authors.initials: M
authors.lastname: Behpour
authors.forename: Sayed Mehdi
authors.initials: SM
authors.lastname: Ghoreishi
authors.forename: Ebrahim
authors.initials: E
authors.lastname: Honarmand
authors.forename: Masoud
authors.initials: M
authors.lastname: Salavati-Niasari
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D002138:Calibration; D002244:Carbon / Q000737:chemistry; D058266:Dielectric Spectroscopy / Q000379:methods; D004298:Dopamine / Q000097:blood* / Q000302:isolation & purification* / Q000652:urine*; D055664:Electrochemical Techniques / Q000379:methods; D004566:Electrodes; D005663:Furans / Q000737:chemistry / Q000378:metabolism; D006046:Gold / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D016014:Linear Models; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism; D014527:Uric Acid / Q000032:analysis*
chemical_list: C559750:2-(((2-sulfanylphenyl)imino)methyl)phenol; C559751:2-((Z)-1-(3-furyl)methylidene)amino-1-benzenethiol; D005663:Furans; D010636:Phenols; D013438:Sulfhydryl Compounds; D014527:Uric Acid; D002244:Carbon; D006046:Gold; D001205:Ascorbic Acid; D004298:Dopamine