Coulometric analysis of organic compounds (review)

Methods for electrogeneration of coulometric titrants are described, and oxidation-reduction properties and other characteristics of the titrants are discussed. Examples of titrants used for determination of organic compounds of various classes in nonaqueous and mixed solvents are given. ©1998 Plenum Publishing Corporation

Galvanostatic coulometric determination of salicylic acid and some of its derivatives using electrogenerated halogens

Reactions of electrogenerated bromine and chlorine with salicylic acid and some of its derivatives were studied. Procedures for the galvanostatic coulometric determination of 2.4 to 19.2 μg/mL of salicylic, acetylsalicylic, para-aminosalicylic acids and mesalazine in model solutions and medicinal preparations with electrogenerated halogens were developed (RSD varied from 1 to 5%). The end-point of coulometric titration was determined amperometrically with two polarized platinum electrodes

Determination of copper and cadmium by atomic absorption spectrometry with electrochemical and sorption preconcentration

A method is proposed for the determination of copper and cadmium by atomic absorption spectrometry in a propane-butane-air flame with electrochemical and sorption preconcentration. Electrochemical preconcentration was performed on metal (tantalum, titanium, molybdenum, and platinum), glassy-carbon, and spectrographic graphite electrodes. Sorption preconcentration was performed on filter paper with immobilized dithizone, 8-hydroxyquinoline, and rubeanic acid. It is demonstrated that copper and cadmium can be determined in water within the concentration range 1-10 μg/L

Galvanostatic coulometric determination of aromatic amine derivatives in pharmaceutical preparations using electrochemically generated bromine

Procedures were developed for the coulometric determination of aromatic amine derivatives in model solutions and pharmaceutical preparations (anaesthesine, novocaine, novocainamide, paracetamol, streptocid, sulgin, sodium sulfacyl, ethazole, sulfadimezine, norsulfazole, and sulfamethoxazole) using electrochemically generated bromine with RSD of 1 to 5%. The stoichiometric coefficients of reactions were determined, and possible mechanisms were proposed for the reactions of bromine with the above preparations

Coulometric determination of purine alkaloid series with electrogenerated chlorine

In acid solution, caffeine, theobromine, and theophylline are rapidly and quantitatively oxidized with electrogenerated chlorine in a stoichiometric ratio of 2 : 5 to give alloxan and urea. Procedures for the coulometric determination of microgram amounts of caffeine, theophylline, and theobromine in model solutions, caffeine in tea and coffee samples, and caffeine and theophylline in some pharmaceutical preparations were developed. © 2001 MAIK "Nauka/Interperiodica"

Coulometric determination of the antioxidant capacity of tea extracts using electrogenerated bromine

A coulometric procedure based on the reaction between aqueous extracts of tea with electrogenerated bromine compounds was proposed for the rapid estimation of the antioxidant capacity of different kinds of tea. The antioxidant properties of tea with respect to bromine are mainly due to naturally occurring flavonoids, tannins, and some vitamins. Photometric and coulometric data for black teas exhibit good correlation. © 2001 MAIK "Nauka/Interperiodica"

Electrochemical generation of hypohalogenite ions and its application to determining pharmaceuticals

The optimum conditions for the electrochemical generation of hypohalogenite ions (current efficiency, actual redox potentials, and pH ranges) in the coulometric titration of sulfanilamide preparations, acid hydrazides and amides, amino acids, and sulfur-containing pharmaceuticals are determined. © 1997 MAEe Cyrillic signK Hayκa/Interperiodica Publishing

Voltammetric Behavior of Glucose and Other Carbohydrates on Metal Electrodes

The potential ranges of catalytic oxidation of glucose and some other carbohydrates on copper, silver, nickel, cobalt, and gold electrodes were determined, and possible schemes of electrochemical and chemical reactions were proposed. The ranges of the linear dependence of the current on the glucose concentration were established, and the possibility was shown of voltammetric determination of glucose in model solutions and human blood serum

Determination of fat-soluble antioxidants by galvanostatic coulometry using electrogenerated oxidants

It was found that vitamin E reacts with electrogenerated chlorine and bromine, as well as with silver (I) and vanadium(V) in the ratio 1:1 to form α-tocopherylquinone. Vitamin A reacts with electrogenerated halogens in the ratio 1:3. Individual fat-soluble antioxidants were determined in model solutions at the milligram level with RSD between 1 and 4%. The bromine-scavenging antioxidant capacity of some vegetable oils and animal fats was evaluated

Voltammetric flow-injection determination of glucose in blood serum

A method for voltammetric flow-injection determination of glucose in blood serum is described by which the catalytic current associated with formation of the Fehling reactant on a metallic copper electrode is used as the analyte signal. The analyte signal is proportional to the concentration of glucose in the range of 1 × 10-4 - 1 × 10-3 M, and the throughput of the FIA system is 50 samples/h. The detection limit for determination of glucose is found to be 2 μg/ml. © 1999 Plenum Publishing Corporation