Electrochemical recording

Adams, R. N., 1978, In vivo electrochemical recording—a new neurophysiological approach,... 

Knott, P. J., Hutson, P. H., Scraggs, R. P., and Curzon, G., 1981, Electrochemical recording of brain catecholamine and serotonin release during behavioral changes, in Function and Regulation of Monoamine Enzymes Basic and Clinical Aspects (E. Usdin, N. Weiner and M. B. H. Youdin, eds.), pp. 771-780, Macmillan, New York. 

Figure 21 AMPH exposure decreases the quantal amplitude of individual release events from PC 12 cells. Randomly chosen amperometric electrochemical records of quantal release for (A) a control cell and (B) a cell that has been incubated in 10 i,M d-AMPH for 10 min. Cells were stimulated by local perfusion (30 nL of 1 mM nicotine in 105 mM KCl saline) to induce vesicular exocytosis. (C) A histogram displaying the percentage of peak sizes in paired control and AMPH-treated cells. Peaks are combined in intervals of 30,000 molecules. The lower limit of each bin size is shown on the abscissa. All data were obtained using a 5 pm carbon fiber electrode held at 0.65 V vs. SSCE. (Reproduced from J. Neu-rosci. with permission [52].)...

Fig. 7. Effect of an NO-synthase inhibitor (L-arginine p-nitroanilide) on the differential normal pulse voltammetry measurements obtained at a carbon fiber/[(H20)Fe PWii039] -doped poly(Af-methyl pyrrole)/Nafion microelectrode in the rat brain. Electrochemical recording between 0.4 and 1.35 V (vs. Ag/AgCl) at 10 mVs with one cycle every 2 min. The indicated potential corresponds to the oxidation peak of NO and the zero time indicates the injection of the inhibitor into the rat. (From [150].)...

Burmeister JJ, Moxon K, Gerhardt GA (2000) Ceramic-based multisite microelectrodes for electrochemical recordings. Analytical Chemistry 72 187-192. 

What is the purpose of waiting 10 s after mixing the contents of the electrochemical cell before recording the voltammogram ... 

The changes in the optical absorption spectra of conducting polymers can be monitored using optoelectrochemical techniques. The optical spectmm of a thin polymer film, mounted on a transparent electrode, such as indium tin oxide (ITO) coated glass, is recorded. The cell is fitted with a counter and reference electrode so that the potential at the polymer-coated electrode can be controlled electrochemically. The absorption spectmm is recorded as a function of electrode potential, and the evolution of the polymer s band stmcture can be observed as it changes from insulating to conducting (11). 

Fig. 3-7 Electrochemical depolarization after switching off the protection current for different recording speeds (polarization of steel in artificial soil solution for 200 h).

Emission spectra have been recorded for four aryl-substituted isoindoles rmder conditions of electrochemical stimulation. Electrochemiluminescence, which was easily visible in daylight, was measured at a concentration of 2-10 mM of emitter in V jV-dimethylformamide with platinum electrodes. Emission spectra due to electrochemi-luminescence and to fluorescence were found to be identical, and quantum yields for fluorescence were obtained by irradiation with a calibrated Hght source. Values are given in Table X. As with peak potentials determined by cyclic voltammetry, the results of luminescence studies are interpreted in terms of radical ion intermediates. ... 

Stationary microwave electrochemical measurements can be performed like stationary photoelectrochemical measurements simultaneously with the dynamic plot of photocurrents as a function of the voltage. The reflected photoinduced microwave power is recorded. A simultaneous plot of both photocurrents and microwave conductivity makes sense because the technique allows, as we will see, the determination of interfacial rate constants, flatband potential measurements, and the determination of a variety of interfacial and solid-state parameters. The accuracy increases when the photocurrent and the microwave conductivity are simultaneously determined for the same system. As in ordinary photoelectrochemistry, many parameters (light intensity, concentration of redox systems, temperature, the rotation speed of an electrode, or the pretreatment of an electrode) may be changed to obtain additional information. 

Time-resolved microwave conductivity measurements with electrodes in electrochemical cells can conveniently be made with pulsed lasers (e.g., an Nd-YAG laser) using either normal or frequency-doubled radiation. Instead of a lock-in amplifier, a transient recorder is used to detect the pulse-induced microwave reflection. While transient microwave experiments with semiconducting crystals or powders have been performed... 

Finally, the recording of many signals from the output of the analytic and electrochemical instrumentation requires a reliable multi-pen recorder or an equivalent recording system based on a data acquisition card and appropriate software. The recorded signals are normally in the range of a few mV to 10V. The use of reliable temperature controllers and thermocouples is also crucial for the success of the experiments. A lot of suppliers of such equipment can be easily found and will not be reported here. 

The term polarography basically refers to a method, where the current flowing across the electrochemical interface is recorded as a function of the applied electrode potential, historically in most cases a mercury electrode is involved. Thus polarography might be called also voltammetry. This sometimes results in confusing terms like e.g. AC voltammetry, which is obviously equivalent to AC polarography (see following entry). (Data obtained with this method are labelled DCP.)... 

This is called the SrnI mechanism," and many other examples are known (see 13-3, 13-4,13-6,13-12). The lUPAC designation is T+Dn+An." Note that the last step of the mechanism produces ArT radical ions, so the process is a chain mechanism (see p. 895)." An electron donor is required to initiate the reaction. In the case above it was solvated electrons from KNH2 in NH3. Evidence was that the addition of potassium metal (a good producer of solvated electrons in ammonia) completely suppressed the cine substitution. Further evidence for the SrnI mechanism was that addition of radical scavengers (which would suppress a free-radical mechanism) led to 8 9 ratios much closer to 1.46 1. Numerous other observations of SrnI mechanisms that were stimulated by solvated electrons and inhibited by radical scavengers have also been recorded." Further evidence for the SrnI mechanism in the case above was that some 1,2,4-trimethylbenzene was found among the products. This could easily be formed by abstraction by Ar- of Ft from the solvent NH3. Besides initiation by solvated electrons," " SrnI reactions have been initiated photochemically," electrochemically," and even thermally." ... 

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