Basic Exchange Resin Research Articles

Improved Synthesis and Rapid Isolation of Millimole Quantities of Adenylylsulfate

An improved enzymatic method for the synthesis of adenylysulfate (APS) from adenosine 5'-phosphate using APS-reductase from Thiobacillus denitrificans is described. Isolation of millimole quantitities of this sulfur nucleotide is achieved rapidly by means of ion exchange chromatography on a strongly basic ion exchange resin. A facile and reproducible desalting procedure is described.

High Pressure Liquid Chromatographic Determination of Saccharides in Corn Sirups: Collaborative Study

Abstract A liquid chromatographic method for quantitative analysis of saccharides in corn sirup was investigated. Fructose, glucose, and related saccharides are separated on an Aminex 50W-X4, calcium form, cation exchange column or, alternatively, on an Aminex Q15-S, calcium form, cation exchange column. Water is the solvent. All carbohydrate components in the sirup elute from the column, permitting normalized computation vs. synthetically prepared standards. The corn sirup samples are diluted to an approximate dry substance and injected directly into the chromatograph. When required, interfering ionic material is removed with the aid of a mixed strong acid-weak base ion exchange resin. The reproducibility and repeatability coefficients of variation for fructose (on samples ranging from 15 to 90% fructose) are 0.9 and 0.3%, respectively. The reproducibility and repeatability coefficients of variation for glucose (on samples ranging from 8 to 50% glucose) are 1.4 and 0.5%, respectively. The method has been adopted as official first action.

Regeneration of weak base ion exchange resins

The present paper reports investigations of the regeneration of weak base ion exchange resins. A mathematical model of reaction-coupled diffusion has been applied to the regeneration kinetics. Photographic evidence is given to the sharp loading profiles resulting from that theory. By comparison of experimental data with theoretical results interdiffusion coefficients in the resin phase have been determined and their different dependency on system parameters is shown.

Effect of polystyrene anionite on equilibrium ratio between diastereomeric copper complexes of alanine dipeptides

1. A study was made of the sorption of the complex of L-Ala-L-Ala with the Cu(II) ion and salicylaldehyde on a strongly basic ion-exchange resin and the effect of the concentration and form of the salicylaldehyde and Cu(II) ion on it. 2. The epimerization equilibrium constant, equal to the ratio of the concentration of copper N-salicylidene-D-alanyl-L-alaninate to the concentration of copper N-salicylidene-L-alanyl-L-alaninate on the resin, differs from the epimerization constant in solution.

Determination of 1-β- d-ribofuranosyl-1,2,4-triazole-3-carboxamide (virazole) in blood and urine by chemical ionization-mass fragmentography

A combined gas chromatographic-mass spectrometric technique is described for the quantification of virazole in serum and urine. Proteins are removed by molecular filtration, lipids by extraction with dichloromethane and interfering endogenous constituents by acidic and basic ion-exchange resins. Virazole is quantified by monitoring the protonated molecular ions of the fully silylated derivatives of virazole ( m/e 533) and the arabinose analog (internal standard) obtained by methane chemical ionization. The detection limit is 150 pg (0.6·10 −12 mole) of virazole injected. In serum 10 ng/ml (4·10 −8 mole) can be detected, 25 ng/ml quantified. In urine 0.5 μg/ml can be quantified without preconcentration. Virazole was detected in serum for at least 96 h at the 70-ng/ml level.

Application of weak base ion-exchange resins for removal of proteins

Application of weak base ion-exchange resins for removal of proteins

The separation of methyl ethers of methyl 2-acetamido-2-deoxy- D-glucopyranosides on a strongly basic ion-exchange resin

The methyl ethers of methyl 2-acetamido-2-deoxy-α- and β- D-glucopyranoside can be isolated on a preparative scale by chromatography on Dowex-1(HO −) resin. This procedure greatly simplifies the purification of methyl ethers, and has been used to isolate the methyl ethers produced by partial methylation of methyl 2-acetamido-2-deoxy-β- D-glucopyranoside. The separations are thought to depend on an ion-exchange process in which all the free hydroxyl groups are involved. It is concluded that the following acidity sequence holds: HO-4>HO-3>HO-6.

ChemInform Abstract: CHROMATOGRAPHY OF INORGANIC IONS ON TEAE‐CELLULOSE LAYERS IN HYDROCHLORIC ACID MEDIA

AbstractDas Adsorptionsverhalten einer großen Anzahl anorganischer Ionen an Triäthylaminoäthylcellulose wird in HCl‐sauren Medien mit und ohne Methanolzusatz untersucht.

Chromatography of Inorganic Ions on TEAE-cellulose Layers in Hydrochloric Acid Media

Abstract The ion-exchange behavior of inorganic ions on TEAE-cellulose was investigated in hydrochloric acid media with and without methanol. Adsorbabilities are low relative to those on strongly basic ion-exchange resin, varying with acid concentration in line with gradual building-up of chlorocomplexes.

Studies on a microchemical method for the determination of the degree of polymerization of neutral oligo- and polysaccharides. I. Quantitative separation of trace amounts of alditols from mixtures with a large excess of monosaccharides.

A method has been devised for the quantitative separation of trace amounts of alditols from mixtures with large amounts of monosaccharides, using a strongly basic ion-exchange resin. Ten kinds of common reducing monosaccharides used were strongly retained by a very basic anion-exchange resin in the hydroxyl form, whereas the corresponding alditols showed no significant affinity for the basic resin. Model studies showed excellent recoveries of alditol from known mixtures of alditol and the corresponding aldose at ratios in the range from 1 : 1X10(3) TO 1 : 1X10(4) (by weight). Application of this procedure to dextrans after reduction and hydrolysis resulted in quantitative separation of the terminal alditol.

Radioisotope studies of carboxyl sites on strong acid and strong base ion-exchange resins derived from polystyrene

The pH-dependent distribution of carrier-free radioisotopes between aqueous phases at constant ionic strength and polystyrene-divinylbenzene type exchangers reveals the presence of a secondary exchange function attributable to carboxyl groups. Cation- and anion-exchangers of the sulphonate and quaternary ammonium types possess this additional cation-exchange capacity which is, however, relatively very low in currently available commercial resins. Its influence on separations involving radioisotopes of high specific activity is discussed.

Anion-exchange behavior of various metals in hydrazoic acid media

The adsorption characteristics for 43 metals on a strongly basic ion-exchange resin Bio-Rad AG1 were examined in 0.5 M hydrazoic acid solution. The distribution coefficients for V(IV), Fe(III), Cu(II), Zn, Se(IV), Mo(VI), Pd(II), Cd, In(III), Rc(VII), Hg(II) and U(VI), which showed very strong adsorption except for Cd, were measured as a function of hydrazoic acid concentration over the range 0.05–0.5 M. Favorable differences in the distribution coefficients allow useful two- and three-component separations such as Co(II)-Fe(III), As(III)-V(IV), Cd-Zn, Cd- Hg(II), Te(IV)-Se(IV), Th-U(VI), Mn(II)-Mo(VI)-Re(VII), to be achieved on a small column.

The removal of organic matter with a weakly basic macroreticular ion-exchange resin : A case history

Natural waters containing organic pollutants have a strong tendency to foul anionic exchange resins irremediably. The use of various types of scavenging resins is discussed and results are given on trials carried out at a chemical plant. The conclusion is drawn that a proper analysis of organic matter present in water cannot be made and that consequently it is difficult to determine which types of scavengers are the most suitable. The paper suggests a principle of calculating weakly basic macroreticular resins into the flow system so as to function both as a scavenger and a weakly basic ion-exchange resin.

Phenolic metabolites of DL-norgestrel: a method for the removal of 1-hydroxylated metabolites, potential sources of phenolic artifacts.

ABSTRACT The identification of 1β-hydroxynorgestrel among the urinary metabolites of dl-norgestrel and the facile transformation of this compound under mild alkaline conditions to a potentially oestrogenic phenol provide an experimental basis for the conclusion advanced by others that the oestrogens present in the urine of subjects treated with synthetic progestens are artifacts formed during analytical work-up. A method has been devised which eliminates 1-hydroxylated metabolites as potential sources of phenolic artifacts. This method is based on the reduction by NaBH4 of the 1-hydroxy-4-en-3-one grouping in the A ring thereby excluding the possibility of aromatization during later fractionation on a basic ion exchange resin that separates neutral from phenolic metabolites. In the urines of women treated with 14C-dl-nogestrel, only 0.17–0.27% of the dose is found to have phenolic properties when this method is used. Two of the phenolic metabolites, 18-homoethynyloestradiol and 16β-hydroxy-18-homoethynyloestradiol, are present in amounts smaller than 0.01 % of the dose. Without the reduction steps the percentages are noticeably higher, indicating artifact formation under alkaline conditions. Similar results were obtained with urines from African Green Monkeys (Cercopithecus Aethiops) that had been dosed with 14C-dl-norgestrel. Radiolabelled 18-homoethynyloestradiol and 16β-hydroxy-18-homoethynyloestradiol were isolated from monkey urine and their identity confirmed by gas chromatography-mass spectrometry.

The Chemical Structure of Tryptophanase from Escherichia coli: III. ISOLATION AND AMINO ACID SEQUENCE OF THE TRYPTIC PEPTIDES

Abstract Sodium borohydride-reduced, carboxymethylated holotryptophanase was digested with trypsin, and the resulting peptides were purified by column chromatography on basic and acidic ion exchange resins, and by paper chromatography and electrophoresis. The isolation and sequence determinations of 13 peptides, including the NH2- and COOH-terminal peptides, those containing carboxymethylcysteine or tryptophan, and that containing the pyridoxyllysine residue (Lys(Pxy)) are reported here, together with a summary of the sequences of a total of 54 tryptic peptides present in the digest. The NH2-terminal peptide, Met-Glu-Asn-Phe-Lys, and the COOH-terminal peptide, Leu-Lys-Glu-Val, were isolated, and an extended sequence at the COOH-terminal end of tryptophanase was proposed to be His-Thr-Phe-Ala-Lys-Leu-Lys-Glu-Val on the basis of carboxypeptidase A experiments and the sequence of an isolated pentapeptide. The amino acid sequence of an extended portion of the peptide chain around the reduced pyridoxal 5-phosphate residue was determined to be Tyr-Ala-Asp-Met-Leu-Ala-Met-SerAla-Lys-Lys(Pxy)-Asp-Ala-Met-Val-Pro-Met-Gly-Gly-Leu-Leu-Cys(Cm)-Met-Lys. Tryptophanase contains 2 tryptophan and 6 cystine residues per subunit of 55,000 molecular weight, and two distinct tryptophan peptides and five distinct carboxymethylcysteine peptides were isolated and sequenced. The studies thus support the view that this subunit contains a single peptide chain. Of a total of about 474 amino acid residues per subunit, 411 were recovered in the 54 tryptic peptides so far studied.

The quantitative separation of chromium(VI) from other elements with a strongly basic anion-exchange resin

Previous work has shown that chromium(VI) on a strongly basic exchange resin in sulphuric acid solution cannot be quantitatively separated from other metal ions because of partial reduction of the chromium(VI) to chromium(III). The present investigations have demonstrated the complete retention of chromium(VI) by the resin in alkaline solutions, thus permitting the separation of chromium from many elements, which can be precipitated as hydroxides, and also from amphoteric elements, which can be eluted from the resin with alkaline solutions. Finally, chromium(VI) can be quantitatively removed from the resin with 8 to 10 per cent. sodium carbonate solution or, more satisfactorily, with an aqueous solution of a mixture of sodium hydrogen carbonate and sodium carbonate.

Anomalous ion-exchange behaviour exhibited by aged acid-free uranyl nitrate solutions

A comparison of the ion-exchange behaviour of stoicheiometric acidfree freshly prepared and strongly aged (7–8 years) uranyl nitrate solutions has been made by means of different cation-exchange and anion-exchange resin systems. While the freshly prepared solutions undergo completely normal stoicheiometric anionic and cationic exchange when percolated through strongly acidic or basic ion-exchange resins, the aged solutions show a strikingly anomalous cation-exchange behaviour since the uranyl cation exhibits an apparent net electrical charge of about 4 +. On the basis of these findings it is concluded that proper attention should be paid to possible restrictions in the applicability of cation-exchange resins for the determination of free acidity in uranyl nitrate solutions, especially when dealing with aged solutions of very low free acidity.

The separation of glycosides on a strongly basic ion-exchange resin: An interpretation in terms of acidity

The anomeric methyl glycopyranosides of D-glucose, D-mannose, D-galactose, 2-amino-2-deoxy- D-glucose, 2-acetamido-2-deoxy- D-glucose, 2-acetamido-2-deoxy- D-mannose, and 2-acetamido-2-deoxy- D-galactose were separated on a preparative scale, in gram amounts and in a good yield, by using Dowex-1 columns in the hydroxide form. The separation of these glycosides on the basic column is assumed to be due to an ion-exchange process involving ionisation of one of the hydroxyl groups of the glycosides. The acidity of the glycosides is explained in terms of the anomeric effect and other forms of dipole interaction.

The Separating Determination Method of the Preservatives by Ion-Exchange Chromatography (I)

More than two kinds of the preservatives are used frequently, in the market foodstuffs. In this paper, the separating determination method for the preservatives by use of the column of the strongly basic ion-exchange resin (DOWEX 2X8-Cl- form) was described. As the eluents, the hydrochloric acid mixed with methanol of the various concentrations were used selectively. The results obtained from the experiments are as follows:1) For seven examples of the mixtures of preservatives, the separating methods of their ingredients were accomplished.2) The interference of the other substances such as the decomposed products from sugar, vanillin and ethyl vanillin, could be romoved from the preservatives.

The absorption of carbon dioxide by weak base ion exchange resins

AbstractA study of the feasibility of using ion exchange resin systems for carbon dioxide absorption from gas streams was completed with the conclusion that such a system could compete very successfully with atmospheric control systems now in use. A detailed study of such a system based on polyethylenimine showed that this material is superior to any of the commercially available weak base resins tested. The kinetic data obtained correlated very well when a model was postulated that was based on diffusive transfer through a gas film, a water film, and the resin particle in series, with diffusion with the resin particle as the rate determining step.