Ya. I. Korenman

Solvent extraction—atomic absorption determination of chromium(VI) in soils

The extraction of chromium(VI) from aqueous saline solutions (NaNO3) using a trioctylamine solution in toluene was studied in order to determine chromium(VI) in soil samples by atomic absorption spectrometry. It was found that the quantitative recovery of chromium(VI) was attained after extraction with the 0.1 M extractant solution (pH 1.5) for 15 min followed by-back extraction with 4 M HNO3. Chromium(III) was not extracted under these conditions

The distribution coefficients of phenol and substituted phenols in the ammonium sulfate-poly-N-vinylpyrrolidone-water system

The extraction of phenols from water-salt solutions was performed using a water-soluble polymer (poly-N-vinylpyrrolidone). The distribution coefficients, the degree of extraction of 13 phenols, and interrelation between the extraction characteristics and structure of distributed compounds were determined. The conditions of the process were optimized to provide maximum extraction of phenols by poly-N-vinylpyrrolidone from water-salt solutions.

Effective systems based on hydrophilic polymers for extraction of phenols from aqueous solutions

Water-soluble polymers (poly-N-vinylpyrrolidone, poly-N-vinylcaprolactam, polyethylene glycol) were used for the first time for extraction of phenols from aqueous solutions. The influence exerted by pH of the aqueous solution and kind of the polymer on the degree of recovery of phenol and some of its methyl and nitro derivatives was elucidated. The correlation between the structure and extraction characteristics of phenols was interpreted.

Extraction-chromatographic determination of sulfonated azo dyes in aqueous solutions

The extraction of sulfonated azo dyes E102, E110, E122, E124, and E129 from aqueous solutions using hydrophilic solvents and their mixtures in the presence of a salting-out agent (ammonium sulphate) has been studied. Some regularities of extraction have been revealed. The composition of the mobile phase has been optimized and a procedure has been proposed for the identification and determination of the dyes in aqueous solutions by thin-layer chromatography in concentrations of 0.1–0.01 μg/L. An office scanner and a personal computer have been used to process the results of the separate determination of the dyes.

Extraction Preconcentration of Naphthols and Phenol with Solvent Mixtures Impregnated into Polyurethane Foam

The extraction of phenol and naphthols with isomolar mixtures of nonane and tributyl phosphate, dibutyl phthalate, or hexane impregnated in ester-based polyurethane foam was studied. The optimum conditions for the extraction–adsorption preconcentration (equilibration time, the pH of the solution, the volume of the test sample, the mass of the adsorbent pellet, and the nature and composition of the mixture applied to polyurethane foam) were determined. A procedure providing the 250- to 350-fold preconcentration of phenol and naphthols is proposed for quantitative extraction.

Extraction and Gas-Chromatographic Determination of Phenol and Cresols in Soil

The effects of the acidity of an aqueous solution, the time of moistening a soil sample, and the time of ultrasonic desorption on the extraction of phenols from soils were studied. The optimum conditions were found. A procedure was developed for the gas-chromatographic determination of 0.05–50 mg/kg of phenol and o- and p-cresols in soil with an error of 10–25%. The time of analysis was 40 min.

Distribution coefficients of vitamin B2 in hydrophilic organic solvent-aqueous salt solution systems

Distribution coefficients of vitamin B2 in hydrophilic solvent (n-butanol, isopropanol, acetone, ethyl acetate, and their mixtures)-aqueous salt (potassium chloride, sodium fluoride, and ammonium sulfate salting-out agents) solution systems were calculated. The synergic effect and optimum proportions of components in the solvent mixture for efficient extraction of vitamin B2 from aqueous solutions were established.

Regularities in the extraction of B group vitamins with synthetic water-soluble polymers

Common regularities in the extraction of vitamins B1, B2, B6, and B12 from aqueous solutions of polymers (poly-N-vinylpyrrolidone, poly-N-vinylcaprolactam, and polyacrylamide) are studied. The effect of the polymer’s concentration and its structure on the distribution coefficients and the degree of extraction of the vitamins is established. Effective systems for extracting B group vitamins from water-salt solutions are developed as a result of screening stable two-phase systems based on water-soluble polymers.

Liquid-liquid distribution of aromatic α-amino acids in multicomponent systems

Distribution coefficients and recovery factors of phenylalanine, tyrosine, and tryptophan are measured in extraction systems with butanol, pentanol, acetone, and ethyl acetate, their binary and ternary mixtures, and water-soluble polymers. Extraction conditions—extractant composition, salting-out agents, and pH—are optimized. Efficient systems providing maximum quantitative characteristics of the process of liquid-liquid distribution of aromatic α-amino acids are proposed.

Extraction separation and electrophoretic determination of tyrosine and glycine

Conditions for extraction separation of tyrosine and glycine in extracts based on a mixture of hydrophilic solvents were developed. The effect of the content of a salting-out agent on the distribution coefficients of tyrosine and glycine in a system constituted by a mixture of hydrophilic solvents (n-butanol-ethyl acetate-acetone) and an aqueous-salt solution was studied. Mathematical methods of experiment design were used to optimize the separation conditions of amino acids.