Fabrication, characterization, and application of a diamond microelectrode for electrochemical measurement of norepinephrine release from the sympathetic nervous system

Park, Jin-Woo; Quaiserová-Mocko, Veronika; Pecková, Karolina; Galligan, James J.; Fink, Gregory D.; Swain, Greg M.

doi:10.1016/j.diamond.2005.11.008

Cited by 68 publications

(95 citation statements)

References 71 publications

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“…We recently reported on a CE-EC method useful for the determination of endogenous NE levels in healthy and diseased organ tissues that are sympathetically innervated [27,28]. It was shown that chamber-specific levels of NE could be determined by this method for sympathetically innervated and chemically denervated rat hearts [28].…”

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confidence: 98%

CE coupled with amperometric detection using a boron‐doped diamond microelectrode: Validation of a method for endogenous norepinephrine analysis in tissue

et al. 2008

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The level of endogenous norepinephrine (NE) in several tissue types was determined by CE with amperometric detection. We report herein on the method validation by HPLC using both amperometric and coulometric detection (CD). Keys to the method were the use of a diamond microelectrode for detection and off-line SPE for sample preparation. The run buffer was a 250 mM borate solution adjusted to pH 8.8 with potassium hydroxide. The diamond microelectrode exhibited a low and stable background current, and a low peak-to-peak noise < or =0.65 pA at the detection potential of +0.86 V versus Ag/AgCl. For standard solutions, the detector signal (i.e., oxidation current) changed linearly with the NE concentration (r(2) = 0.999) between 60 and 1000 nmol/L with an estimated LOD of 51 nmol/L (S/N = 3) and a response variability of 4.5% (RSD, n = 5). An Oasis MCX sorbent was used for SPE and the procedure produced an NE recovery of 95.1 +/- 5.6% (n = 6) from tissue homogenates. NE levels in the spleen, small intestine, and heart of a normotensive rat were found to be in the range of 0.77-0.97, 0.22-0.32, and 0.29-0.45 microg/g tissue (n = 3), respectively.

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confidence: 98%

CE coupled with amperometric detection using a boron‐doped diamond microelectrode: Validation of a method for endogenous norepinephrine analysis in tissue

et al. 2008

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“…A microelectrode for end-column amperometric detection was reported (74). The electrode was prepared by depositing a boron-doped diamond thin film on a Pt wire.…”

Section: Detectionmentioning

confidence: 99%

Capillary Electrophoresis in Bioanalysis

2008

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Science reports ∼4800 hits on capillary electrophoresis (CE) including 410 reviews. Because of the prominence of CE techniques in bioanalysis, we decided make them the focus of this review and selected 200 hundred papers representing advances in this field. The selected papers cover advances in CE theory, instrumentation, and methodologies that are specific to various analytes of biological origin or relevance. The group of analytes includes nucleic acids, proteins and peptides, carbohydrates, lipids, single cells, and bioparticles. In addition, we have included advances in the use of CE to define functional assays or to investigate biomolecular interactions. The use of microfabricated devices for CE analysis was not included because this is already covered in other review. Technique Developments Separation SchemesDetermining the velocity of the electroosmotic flow (EOF) and how it changes during an electrophoretic separation is still an important research topic. A simple method for EOF measurements using so-called thermal marks was reported (1). Here, a tungsten filament caused punctual heating at the capillary wall and caused a perturbation in the electrolyte concentration. A sequence of these "thermal marks" then migrated with the EOF until each mark reached and was detected by a conductivity detector. The feasibility of using thermal marks as internal EOF standards in different separation systems was thereby demonstrated.Isoelectric focusing separates amphoteric analytes such as proteins or peptides by the differences in their isoelectric points. Most of the reports on capillary isoelectric focusing (cIEF) describe an initial focusing phase after which the focused zones are mobilized and detected. A dynamic cIEF method for protein analysis was reported (2). This technique made it possible to control each protein's position and focused width by moving the pH gradient within the capillary through manipulation of the electric fields. An important advantage of this approach is the capability of collecting focused analytes from the central section, suggesting that there may be great potential for introducing selectively focused proteins to a second separation dimension such as LC or CE.Micellar electrokinetic capillary chromatography (MEKC) is typically incompatible with electrospray mass spectrometry (ESI-MS) because the nonvolatile surfactants in the micellar phase result in complicated adduct formation and loss of sensitivity during the electrospray process and because the presence of the organic solvent needed for electrospray may cause instability in the micellar phase. These drawbacks were overcome by using synthetic polymeric surfactants that can work as a pseudostationary phase and provide stable electrospray (3). The polymeric surfactant was made by polymerizing three amino acidderived (L-leucinol, L-isoleucinol, L-valinol) sulfated chiral surfactants. These polymeric

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“…(b) (i) α = 5, (ii) α = 10, (iii) α = 100, the current was calculated using (9) for all large values of "α". (c) (i) α = 0.01, 0.1, 1 (ii) α = 10, (iii) α = 50, and, (iv) α = 100, the current was calculated using (9) and (11) (solid line) (11); (dotted line) (6). Solid lines are compared with points.…”

Section: Neglecting Substrate Concentration Polarization In Solutionmentioning

confidence: 99%

“…Hence (1) reduces to Figure 4: Plot of normalized current "ψ" versus the reaction/diffusion parameter "γ" at a microelectrode modified using a conducting polymer film. (a) (i) α = 0.1, 1, the current was calculated using (6) and (11) for all small and medium values of α. (b) (i) α = 5, (ii) α = 10, (iii) α = 100, the current was calculated using (9) for all large values of "α".…”

Section: Neglecting Substrate Concentration Polarization In Solutionmentioning

confidence: 99%

“…Furthermore, due to their diminished surface area or radii of the electrodes, they are often employed as probes to monitor various chemical events occurring inside the living cell [5][6][7][8]. Ultramicroelectrodes possess many advantages for studying electrochemical kinetics and in electroanalytical applications, imaging, and surface modification [9].…”

Section: Introductionmentioning

confidence: 99%

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Approximate Analytical Solution of Nonlinear Reaction’s Diffusion Equation at Conducting Polymer Ultramicroelectrodes

Anitha¹,

Alwarappan

Rajendran³

2012

ISRN Physical Chemistry

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A theoretical model of reaction/diffusion within conducting polymer microelectrodes is discussed. The model is based on the steady-state diffusion equation containing a nonlinear term related to the Michaelis-Menten kinetic of the enzymatic reaction. An analytical expression pertaining to the concentration of substrate and current is obtained using homotopy perturbation method for all values of diffusion and the saturation parameter. The substrate concentration profile and current response can be used in a large range of concentrations including the non-linear contributions. These approximate analytical results were found to be in good agreement with the previously reported limiting case results.

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Fabrication, characterization, and application of a diamond microelectrode for electrochemical measurement of norepinephrine release from the sympathetic nervous system

Cited by 68 publications

References 71 publications

CE coupled with amperometric detection using a boron‐doped diamond microelectrode: Validation of a method for endogenous norepinephrine analysis in tissue

CE coupled with amperometric detection using a boron‐doped diamond microelectrode: Validation of a method for endogenous norepinephrine analysis in tissue

Capillary Electrophoresis in Bioanalysis

Approximate Analytical Solution of Nonlinear Reaction’s Diffusion Equation at Conducting Polymer Ultramicroelectrodes

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