Voltammetry fast cyclic

Pali), P and Stamford, JA (1993) Real-time monitoring of endogenous noradrenaline release in rat brain slices using fast cyclic voltammetry. 2. Operational characteristics of the alpha2 autoreceptors in the bed nucleus of the stria terminalis, pars ventralis. Brain Res. 608 134-140. 

Comparison with Fast Cyclic Voltammetry and Laser Flash Photolysis... 

An estimate of the pK value for benzaldehyde radical-anion has also been obtained from fast cyclic voltammetry experiments over a range of pH values [14], Interpretation the results obtained in this case requires first deduction of an overall reaction scheme followed by numerical solution of the corresponding set of differential equations allowing simulation of the cyclic voltammogram. Reaction constants are then adjusted to give good simulations over a range of experimental conditions. The pKj can then be extracted from these reaction constants. 

Kruk, Zygmunt L., S. Cheeta, J. Milla, R. Muscat, J. E. Williams, and Paul Willner. 1998. "Real-Time Measurement of Stimulated Dopamine Release in the Conscious Rat Using Fast Cyclic Voltammetry Dopamine Release Is Not Observed During Intracranial Self-Stimulation." Journal of Neuroscience Methods 79 9-19. 

Another important feature is the relative size of the diffusion layer with respect to the double layer. The diffusion-layer dimensions are proportional to the size of the electrode, and can approach the size of the double layer with electrodes of molecular dimensions [95]. This can also occur in other situations explored with microelectrodes. For example, in solutions of very dilute electrolyte, the diffuse double layer extends several nanometers into solution [62]. Alternatively, very fast cyclic voltammetry results in a very small diffusion layer, which may be of dimensions similar to the double layer [46]. In all these situ-... 

Davidson C, Stamford JA. Serotonin efflux in the rat ventral lateral geniculate nucleus assessed by fast cyclic voltammetry is modulated by 5-HT1B and 5-HTm autoreceptors. Neuropharmacology 1996 35 1627-1634. 

Roberts C, Price GW. Interaction of serotonin autoreceptor antagonists in the rat dorsal raphe nucleus an in vitro fast cyclic voltammetry study. Neurosci Lett 2001 300 45-48. 

Fiber electrodes -> microelectrodes in a form of bare fibers as the conductive elements, protruding from the end of an insulator, usually made of carbon fibers of 7-8 pm diameter and sealed in glass capillaries often used for direct measurements (e.g., using fast cyclic voltammetry) of the in-vivo release of oxidiz-able neurotransmitters, such as dopamine, serotonin, norepinephrine, or epinephrine, from living cells. Also used to monitor electric activity of single nerve cells or for diagnostic purposes in electroanalysis. S ee also carbon fiber electrode. 

The time range of the electrochemical measurements has been decreased considerably by using more powerful -> potentiostats, circuitry, -> microelectrodes, etc. by pulse techniques, fast -> cyclic voltammetry, -> scanning electrochemical microscopy the 10-6-10-1° s range has become available [iv,v]. The electrochemical techniques have been combined with spectroscopic ones (see -> spectroelectrochemistry) which have successfully been applied for relaxation studies [vi]. For the study of the rate of heterogeneous -> electron transfer processes the ILIT (Indirect Laser Induced Temperature) method has been developed [vi]. It applies a small temperature perturbation, e.g., of 5 K, and the change of the open-circuit potential is followed during the relaxation period. By this method a response function of the order of 1-10 ns has been achieved. 

Kruk ZL, Cheeta S, Mill J, Muscat R, Willians JEG, Willner P (1998) Real time measurement of stimulated sopamine release in the conscious rat using fast cyclic voltammetry dopamine release is not observed during intracranial self-stimulation. J Neurosci Meth 79 9-19. 

Jones SR, Bowman BP, Kuhn CM, Wightman RM (1996) Development of dopamine neurotransmission and uptake inhibition in the caudate nucleus as measured by fast-cyclic voltammetry. Synapse 24 305-307. 

Xi ZX, Fuller SA, Stein EA (1998) Dopamine release in the nucleus accumbens during heroin selfadministration is modulated by kappa opioid receptors an in vivo, fast-cyclic voltammetry study. J Pharmacol Exp Ther 284 151-161. 

To improve chemical selectivity, a triangular input waveform can be used that separates compounds into resolvable peaks. This form—cyclic voltammetry—can be carried out with high temporal resolution using high scan rates to allow the waveform to be completed in a short time. In fast-scan cyclic voltammetry (also known as fast cyclic voltammetry), waveforms last around 10 ms, and measurements are typically made every 10-200 ms. 

Only the application of fast cyclic voltammetry (in the range of 10-100 kVs-1) at gold ultramicroelectrodes has resulted recently in obtaining65,107 in DMF reversible one-electron oxidation peaks of p-anisidine (68a), p-chloroaniline (68b) and p-bromoaniline... 

Stamford J A, Pali] P, Davidson C and Trout S J 1995 Fast cyclic voltammetry neurotransmitter measurement in real time and real space Bioelectrochem. Bioenerg. 38 289... 

Stamford, J. A, (1990) Fast cyclic voltammetry-measuring transmitter release in real-time. J Neurosci. Meth 34,67—72. 

The adsorption of OH ions on the Pt(lll) plane has been studied by Drazic and coworkers [102] using fast cyclic voltammetry in sodium hydroxide solutions (0.03 to 1 M), under quasi-equilibrium and Tafel approximation conditions. It was shown that the OH ion adsorption is an electrosorption process with one electron exchanged... 

Williams JEG, Millar J, Kruk ZL, A comparison of cut and spark-etched electrodes for fast cyclic voltammetry, Br J Pharmocol, 107, 1992. 

Cyclic voltammetry Square-wave voltammetry Staircase voltammetry Linear-sweep voltammetry Fast cyclic voltammetry Rotating disc voltammetry Stripping voltammetry Hydrodynamic voltammetry Direct current (d.c.) polarography Alternating current (a.c.) polarography Pulse polarography... 

The increase in DA concentration from nanomolar level in extracellular fluid can be provoked by implanting electrodes in the vicinity of axons. Then the concentration changes of DA are measurable by fast cyclic voltammetry. These electrodes stimulate the action potentials. Voltammetric sensors can then be used for monitoring the evoked release of dopamine. The experiment is demonstrated in Fig. 48. When the stimulus is initiated a chemical change is detected within 100 ms. The observed concentration of DA, which is a function of stimulus frequency (60 Hz has been applied), rapidly increases during the stimulation and returns to the baseline once the stimulation ceases. It is evident that a subsecond time resolution is required to observe these events. Further quantitative in vivo measurements are required so that models of the dynamics of this process can be tested [172]. 

R. M. Wightman The technique that we use is normal pulse voltammetry with pulses that are 100 ms long. But in the last 6 months, working with some people at the London hospital we have been using very fast cyclic voltammetry, at 300 V/s and we can get a complete record in 10 ms it gives exactly the same quantitative numbers as 1 showed here. So that is the direction in which certainly all of us will be going. 

The 17 electron radical RSCr(CO)5 could not be detected by ESR. Attempts to observe it directly by fast cyclic voltammetry were not successful either. Indeed, even at scan rates as high as 500 V/s, no indication of reversibility could be obtained for the oxidation wave of the chromium thiolate anion. It can be deduced that the transient radical has a half life time shorter than 50 microseconds. 

Garreau, D. Hapiot, P. Saveant, J.M. (1990). Fast cyclic voltammetry at ultramicroelectrodes Current measurement and ohmic drop positive positive feedback compensation by means of current feedback operational amplifiers. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 281,73-83. 

In reality, there is no absolute proof in favour of either of these mechanisms, but it appears to be generally agreed that cationic coupling is the most important mechanism for the formation of poly(/ -phenylene). It must be emphasized that in the case of the electropolymerization of pyrole and thiophene, which are electropolymerized in much the same way as benzene, the radical-cationic coupling mechanism was proven from kinetic results deduced from ultra-fast cyclic voltammetry experiments [153]. Isotopic studies... 

Palij P, Bull DR, Sheehan Ml, Millar J, Stamford J, Kruk ZL, Humphrey PP (1990) Presynaptic regulation of dopamine release in corpus striatum monitored in vitro in real time by fast cyclic voltammetry. Brain Res 509 172-174. 

These resnlts snggest that PC 12 vesicles can adjust their volume when accommodating different amounts of neurotransmitter to regulate a relatively constant nenrotransmitter concentration. When combined with the results reported from the fast cyclic voltammetry experiments, these findings also suggest that the modulation of qnantal release ultimately affects the time course of receptor stimulation following exocytosis. 

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