Behavior Of Epinephrine Research Articles

Voltammetric determination of epinephrine in the presence of uric acid based on aminated graphene and Ag NPs hybrid membrane modified electrode

A hybrid membrane consisted of aminated graphene and Ag nanoparticles(Ag NPs) was prepared on the surface of glassy carbon electrode(GCE) by cyclic voltammetry(CV) with aminated graphene(GR-NH2) as matrix for immobilizing Ag NPs. The morphology and electrochemical properties of this hybrid membrane were characterized by scanning electron microscopy(SEM) and CV, respectively, and on this membrane, the voltammetric behaviors of epinephrine(EP) were studied in detail. The membrane exhibited excellent eletro-catalytic activities for the redox of EP, and could resolve the electrochemical response of EP and uric acid(UA) into two oxidation peaks. The peak current of EP was linear with its concentration in the ranges of 0.916–18.3 μmol/L and 18.3–184 μmol/L. The detection limit was 2.0 nmol/L(S/N=3). The proposed modified electrode retained the advantages of easy fabrication, high sensitivity and good repeatability for the determination of EP.

Determination of Epinephrine at Different Types of Carbon Paste Electrodes

The voltammetric behavior of epinephrine was investigated by differential pulse voltammetry (DPV) at a carbon paste electrodes (CPE) made of different carbon powders – CR-2, glassy carbon (GC) microparticles, and single-wall carbon nanotubes (SWNT). In Briton-Robinson (BR) buffer solution pH 6, the linear dependence was found for the determination of epinephrine by the given method in the concentration ranges of 1·10−6–1·10−4 (CR-2), 1·10−6–1·10−4 (GC microparticles) and 4·10−6–1·10−4 (SWNT) mol·dm−3. Limits of detection were 8·10−7, 8·10−7, and 2·10−6 mol·dm−3, respectively. The best results were obtained employing CPE containing carbon paste with 50% (m/m) of SWNT, a linear dynamic range being 4·10−7–1·10−4 mol·dm−3 and a limit of detection 2·10−7 mol·dm−3. The attempt to increase the sensitivity by adsorptive accumulation of epinephrine was not successful.

Anodic square-wave stripping voltammetric analysis of epinephrine using carbon fiber microelectrode

The behavior of epinephrine on a carbon fiber microelectrode (CFME) was studied with cyclic voltammetry and square-wave (SW) stripping voltammetry in order to find optimum conditions for its analysis using the CFME. An anodic stripping peak at about 0.20 V (vs. Ag/AgCl) was utilized. Under optimum conditions for anodic stripping (a pH value of 7.4, a deposition potential of − 0.5 V, a deposition time of 90 s, a final potential of 0.8 V, a SW frequency of 20 Hz, a step potential of 5 mV, and an amplitude of 45 mV), the calibration was linear in the concentration range of 0.0∼0.4 mg/L, and the detection limit was found to be 0.009 mg/L with a relative standard deviation 0.18% ( n = 12) at 0.2 mg/L. The analytical performance of the CMFE, which is unmodified, is comparable to or better than other voltammetric results with various modified electrodes.

Voltammetric response of epinephrine at carbon nanotube modified glassy carbon electrode and activated glassy carbon electrode

The electrochemical behavior of epinephrine at activated glassy carbon electrode and carbon nanotube-coated glassy carbon electrode was studied. Epinephrine could exhibit an anodic peak at about 0.2 V (vs. SCE) at bare glassy carbon electrode, but it was very small. However, when the electrode was activated at certain potential (i. e. 1.9 V) or modified with carbon nanotube, the peak became more sensitive, resulting from the increase in electrode area in addition to the electrostatic attraction. Under the selected conditions, the anodic peak current was linear to epinephrine concentration in the range of 3.3×10−7–1.1×10−5 mol/L at activated glassy carbon electrode and in the range of 1.0×10−6–5.0×10−5 mol/L at carbon nanotube-coated electrode. The correlation coefficients were 0.998 and 0.997, respectively. The determination limit was 1.0×10−7 mol/L. The two electrodes have been successfully applied for the determination of epinephrine in adrenaline hydrochloride injection with recovery of 95%–104%.

NANO-GOLD MODIFIED GLASSY CARBON ELECTRODE FOR SELECTIVE DETERMINATION OF EPINEPHRINE IN THE PRESENCE OF ASCORBIC ACID

ABSTRACT The nano-gold modified glassy carbon electrode, which can catalytically oxidize and accumulate epinephrine was obtained by electrodeposition. The effect of pH value and concentration of phosphate buffer solution (PBS) on the electrochemical behavior of epinephrine was studied. Two separating oxidation peaks of epinephrine and ascorbic acid can be observed at the nano-gold modified glassy carbon electrode in cyclic voltammogram. So it can be applied for determination of epinephrine in the presence of ascorbic acid. The peak current of epinephrine is in linear relationship with its concentration in the range of 1.0 × 10−4–1.0 × 10−6 M. Furthermore, the FT-IR spectrometry was employed to study the oxidation of epinephrine.

DIFFERENTIAL PULSE ADSORPTIVE STRIPPING VOLTAMMETRY DETERMINATION OF EPINEPHRINE WITH β-MERCAPTOETHANOL SELF-ASSEMBLED MONOLAYERS MODIFIED ELECTRODE

ABSTRACT β-Mercaptoethanol self-assembled monolayer modified electrode (ME/Au SAMs) has been fabricated on bare gold. ATR-FTIR was used for the characterization and surface structure of the films. The films, as mediator, accelerated the electron transfer and showed an excellent electrocatalytic activity for the oxidation of the EP. The electrochemical behavior of epinephrine at ME/Au SAMs has been studied by cyclic voltammetry. The electrocatalytic mechanism has been explored. At potential of −0.044 V (vs SCE) in pH 4.0 aqueous buffer, a first oxidation wave is observed for epinephrine at the modified electrode (electrochemical oxidation of leucoepinephrine to epinechrome). In contrast, the first oxidation wave is not observed for norepinephrine or dopamine at the same condition. Under the conditions chosen, the modified electrode provides a linear response for epinephrine in the concentration range from 1.0 × 10−7 to 1.0 × 10−4 mol/L by differential pulse adsorptive stripping voltammetry. The detection limit (three times the signal blank/slope) was 3.3 × 10−8 mol/L. The modified electrode could eliminate the interference of norepinephrine, dopamine, and glucose at 10-, 40- and 1000-fold concentration of epinephrine (at 8.0 × 10−6 mol/L), and it has been satisfactorily used for the determination of epinephrine in injection.