Hamidreza Zare-mehrjardi
Abstract
In this study, the surface of the glassy carbon electrode (GCE) is modified with the nanocomposite of graphene oxide (GO)/ ionic liquid (1-Butyl-3-methylimidazolium tetrafluoroborate; [BMIM]BF4). The electrochemical behavior of ascorbic acid (AA) and dopamine (DA) at the surface of the modified glassy ...
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In this study, the surface of the glassy carbon electrode (GCE) is modified with the nanocomposite of graphene oxide (GO)/ ionic liquid (1-Butyl-3-methylimidazolium tetrafluoroborate; [BMIM]BF4). The electrochemical behavior of ascorbic acid (AA) and dopamine (DA) at the surface of the modified glassy carbon electrode was studied using the differential pulse and cyclic voltammetric methods (DPV and CV). The results show good response sensitivity to AA and DA. The acceleration of the electron transfer rate and enhancement of the electroactive surface area is obtained due to a synergistic effect in the concurrent presence of GO and [BMIM]BF4 at the surface of the electrode. The presence of GO caused to a higher specific surface of the electrode, and ionic liquid ([BMIM]BF4) increased the ion conductivity and dispersibility in the modifier layer at the surface of the GCE. These results obtained in optimum conditions, show good peak separation for AA and DA (more than 300 mV), and the sub-micromolar detection limits for them. The obtained results in this work, make the modified GCE very effective in the manufacture of simple devices for the detection of AA and DA in human urine samples.
Ghobad Mansori; Mohammad_Bagher - Gholivand; Zarrin - Es'haghi
Abstract
For the first time, an analytical methodology based ondifferential pulse voltammetry (DPV) at a glassy carbon electrode (GCE) assisted by two multivariate calibration (MVC) models including back propagation-artificial neural network (BP-ANN), non-linear class, and partial least squares-1 (PLS-1), classical ...
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For the first time, an analytical methodology based ondifferential pulse voltammetry (DPV) at a glassy carbon electrode (GCE) assisted by two multivariate calibration (MVC) models including back propagation-artificial neural network (BP-ANN), non-linear class, and partial least squares-1 (PLS-1), classical class, thatthey have been constructed on the basis of non-bilinear first order differential pulse voltammetry (DPV) data,was developed and validated for the simultaneous determination of Ascorbic acid, Uric acid, Acetaminophen, and Noradrenalinto identify which approach offers the best predictions.The baselines of the DPV signals were corrected by asymmetric least square spline regression (AsLSSR) algorithm. Before applying the PLS-1,lack of bi-linearity was tackled by potential shift correction using correlation optimised warping (COW) algorithm. The multivariate calibration (MVC) model was developed as a quaternary calibration modelin a blank human serum sample (drug-free) provided by a healthy volunteer to regard the presence of a strong matrix effect which may be caused by the possible interferents present in the serum, and it was validated and tested with two independent sets of analytes mixtures in the blank and actual human serum samples, respectively.According to the obtained results, the PLS-1 was recommended for simultaneous determination of AA, UA, AC, and NA in both blank and actual human serum samples .
Tahereh Rohani; Sayed Zia Mohammadi; Amirkhosro Beheshti; Hooshang Hamidian; Nasrin Gholamhosein Zadeh
Abstract
Herein, the electrooxidation of ascorbic acid and folic acid, as two essential vitamins, on the surface of the carbon ceramic electrode modified by polydopamine and copper (Cu/PDA/CCE) was investigated. Poly dopamine was fabricated by applying electro deposition conditions. Initial electrochemical characteristics ...
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Herein, the electrooxidation of ascorbic acid and folic acid, as two essential vitamins, on the surface of the carbon ceramic electrode modified by polydopamine and copper (Cu/PDA/CCE) was investigated. Poly dopamine was fabricated by applying electro deposition conditions. Initial electrochemical characteristics were performed to study the behavior of the fabricated electrode for simultaneous detection of two biomolecules. From voltametric studies using the developed electrode, two separated anodic peaks for folic acid and ascorbic acid were found promisingly for concurrent detection of the compounds. Linear calibration diagrams were obtained in the range of 0.5 to 360 μM and 0.83 to 380 μM with detection limits of about 0.031 and 0.057 μM for folic acid and ascorbic acid, respectively. The developed electrode was applied in human urine sample analysis with satisfying results
Ashraf Salmanipour; Sara Hooshmand
Volume 1, Issue 1 , March 2014, , Pages 1-6
Abstract
In this work, an optical sensor for detection of ascorbic acid is described. The sensor is fabricated by casting and spin-coating silica sol-gel doped with 2,6-dichlorophenol indophenol on the glass plates. The sols are in turn obtained by acidic hydrolysis of various precursors such as tetraethoxysilane, ...
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In this work, an optical sensor for detection of ascorbic acid is described. The sensor is fabricated by casting and spin-coating silica sol-gel doped with 2,6-dichlorophenol indophenol on the glass plates. The sols are in turn obtained by acidic hydrolysis of various precursors such as tetraethoxysilane, triethoxymethylsilane and triethoxyoctylsilane in the presence of 2,6-dichlorophenol indophenol as dopant. Prepared sols then were coated on glass plates to form sol-gel films. UV-Vis spectrophotometric properties of 2,6-dichlorophenol indophenol doped in sol-gel films were studied and compared with in solution. At the optimum conditions the response of film to ascorbic acid is fast and linear in 0.07 – 3.34 mmol L-1 range. Detection limit and relative standard deviation of presented sensor for determination ascorbic acid were 0.05 mmol L-1 and 1.32 %, respectively.