Pulsed flow voltammetry

Differential pulse stripping voltammetry Hanging mercury drop or mercury film Stopped flow Extremely sensitive... 

In conclusion, synthetic dyes can be determined in solid foods and in nonalcoholic beverages and from their concentrated formulas by spectrometric methods or by several separation techniques such as TEC, HPLC, HPLC coupled with diode array or UV-Vis spectrometry, MECK, MEECK, voltammetry, and CE. ° Many analytical approaches have been used for simultaneous determinations of synthetic food additives thin layer chromatography, " " derivative spectrophotometry, adsorptive voltammetry, differential pulse polarography, and flow-through sensors for the specific determination of Sunset Yellow and its Sudan 1 subsidiary in food, " but they are generally suitable only for analyzing few-component mixtures. 

The systems that we investigated in collaboration with others involved intermolecular and intramolecular electron-transfer reactions between ruthenium complexes and cytochrome c. We also studied a series of intermolecular reactions between chelated cobalt complexes and cytochrome c. A variety of high-pressure experimental techniques, including stopped-flow, flash-photolysis, pulse-radiolysis, and voltammetry, were employed in these investigations. As the following presentation shows, a remarkably good agreement was found between the volume data obtained with the aid of these different techniques, which clearly demonstrates the complementarity of these methods for the study of electron-transfer processes. 

Wang and Dewald have investigated the possibility of using rapid scan differential pulse voltammetry for the detection of chlorpromazine in flow-injection analysis [160]. The measurement was made with the use of a flow-cell equipped with a carbon paste or a vitreous-carbon disc electrode, a carbon rod auxiliary electrode, and a silver-silver chloride reference electrode. Potential scanning was effected at 2 V/min. 

The mechanism of the iodide formation at platinum immersed in aqueous electrode was recently studied by laser-activated voltammetry in a channel flow cell system [161]. In this technique, solid deposits of iodine are removed from the electrode continuously by short nanosecond high-power laser pulses. By removing deposits on electrode surfaces within a channel flow cell, the voltammetric measurements becomes time independent and data can be analyzed and modeled quantitatively. Laser activation using a 10-Hz pulsed Nd YAG 532-nm laser was shown to remove bulk iodine from the electrode surface so that under sustained pulsed... 

Voltammetry has been adapted to HPLC (when the mobile phase is conducting) and capillary electrophoresis (CE) as a detection technique for electroactive compounds. In this usage, the voltammetric cell has to be miniaturised (to about 1 pi) in order not to dilute the analytes after separation. A metal or carbon microelectrode has a defined potential (vs the reference electrode) depending on the substances to be detected (ions or molecules) and the mobile phase flows through the detection cell (Fig. 19.5). This method of amperometric detection in the pulsed mode is very... 

Berggren, D. (1990) Speciation of cadmium(II) using Donnan dialysis and differential-pulse anodic stripping voltammetry in a flow-injection system. Int. J. Environ. Anal. Chem., 41, 133-148. 

Amperometry is when voltammetry is used at a fixed potential and the current alone is followed. This current is proportional to the concentration of a species in a stirred or flowing solution. It is, therefore, a very suitable detection method for use in flow injection analysis systems and in chromatographic separations its use as a detector for separation techniques is discussed in that section. The current is the result of the electrochemical oxidation or reduction of the analyte after application of a potential pulse across the working and auxiliary electrodes. 

P. W. Alexander and U. Akapongkul, Differential Pulse Voltammetry with Fast Pulse Repetition Times in a Flow-Injection System with a Copper-Amalgam Electrode. Anal. Chim. Acta, 166 (1984) 119. 

L. Ilcheva and K. Cammann, Flow Injection Analysis of Chloride in Tap and Sewage Water Types by Adsorption Differential Pulse Voltammetry. Fresenius Z. Anal. Chem., 322 (1985) 323. 

Lukaszewski Z. and Zembrzuski, W. (1991). Determination of thallium in soils by flow-injection - differnetial pulse anodic stripping voltammetry, Talanta, 39, 221-227. 

---