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PubMed1969

Microbial hydrocarbon co-oxidation. II. Use of ion-exchange resins.

Anion-exchange resins, a weakly basic polystyrene-polyamine type and a macro-reticular type, IR-45 and IRA-93, respectively, were shown to significantly increase yields of acidic products in co-oxidation systems. p-Toluic, 2,3-dihydroxy-p-toluic, and alpha,alpha-cis,cis dimethylmuconic acids, resulting from the oxidation of p-xylene by three cultures of Nocardia, accumulated on the resin in shaken flasks or agar plates during the cultivation. Final product concentration increased with increasing resin concentration. Mineral balances were not affected if the resin was properly conditioned before use.

Acids↗
PubMed2004

Comparison of chromatographic ion-exchange resins. III. Strong cation-exchange resins.

A comparative study was performed on strong cation-exchangers to investigate the pH dependence, efficiency, binding strength, particle size distribution, static and dynamic capacity, and SEM pictures of chromatographic resins. The resins tested included: SP Sepharose XL, Poros 50 HS, Toyopearl SP 550c, SP Sepharose BB, Source 30S, TSKGel SP-5PW-HR20, and Toyopearl SP 650c. Testing was performed with four different proteins: anti-FVII Mab (IgG), aprotinin, lysozyme, and myoglobin. Dependence of pH on retention was generally very low for proteins with high pI. An unexpected binding at pH 7.5 of anti-FVII Mab with pI < 7.5 was observed on several resins. Efficiency results show the expected trend of higher dependence of the plate height with increasing flow rate of soft resins compared to resins for medium and high-pressure operation. Determination of particle size distribution by two independent methods, Coulter counting and SEM, was in very good agreement. The mono-dispersed nature of Source 30S was confirmed. Binding to cation-exchange resins as a function of ionic strength varies depending on the specific protein. Generally, binding and elution at high salt concentration may be performed with Toyopearl SP 550c and Poros 50 HS, while binding and elution at low salt concentration may be performed with Toyopearl SP 650c. A very high binding capacity was obtained with SP Sepharose XL. Comparison of static capacity and dynamic capacity at 10% break-through shows in general approximately 50-80% utilisation of the total available capacity during chromatographic operation. A general good agreement was obtained between this study and data obtained by others. The results of this study may be used for selection of resins for testing in process development. The validity of experiments and results with model proteins were tested using human insulin precursor in pure state and in real feed-stock on Toyopearl SP 550c, SP Sepharose BB, and Toyopearl SP 650c. Results showed good agreement with experiments with model proteins.

Cation Exchange Resins↗
PubMed2003

A comparative study of two chelating ion-exchange resins for the removal of chromium(III) from aqueous solution.

Macroporous resins containing iminodiacetic acid (IDA) groups (Lewatit TP 207 and Chelex-100) were investigated as a function of concentration, temperature and pH for their sorption properties towards chromium(III). The chromium(III) ions sorbed onto the resin and in the equilibrium concentration were determined by inductively coupled plasma spectrophotometer. The maximum sorption for chromium ions was observed at pH 4.5. Solution pH had a strong effect on the equilibrium constant of Cr(III). The equilibrium constants were 320 and 7 at pH value 4.5 for Lewatit TP 207 and Chelex-100 resin, respectively. The Langmuir isotherm was used to describe observed sorption phenomena. Both the sorbents had high bonding constants with Lewatit TP 207 showing stronger binding. The equilibrium related to adsorption capacity and energy of adsorption was obtained by using plots of Langmuir adsorption isotherm. It was observed that the maximum adsorption capacity of 0.288 mmol of Cr(III)/g for Chelex-100 and 0.341 mmol of Cr(III)/g for Lewatit TP 207 was achieved at pH of 4.5. The rise in temperature caused a slight increase in the value of the equilibrium constant (K(c)) for the sorption of chromium(III) ion.

Chelating Agents↗
PubMed1988

Effect of the content of divinylbenzene in ion-exchange resins on the chromatographic separation of alpha-cyclodextrin and glucose.

In the chromatographic separation of alpha-cyclodextrin and glucose, the parameters relating to the adsorption equilibria and rate processes of the solutes were evaluated for the sodium forms of cation-exchange resins with contents of divinylbenzene (DVB) of 2, 4, 6 and 8%. By using these parameters, the chromatograms of the solutes were then calculated. It is concluded that the resin with 6% DVB is most suitable for the chromatographic separation of the solutes on a preparative scale.

Chromatography, Ion Exchange↗
PubMed1981

Drug-polymer combinations. Part 1: The preparation of sustained release drugs by combination with ion exchanging resins.

The preparation of procainamide and propranolol resinates is described. By in vivo experiments with propranolol resinate as model substance the release rate as a function of crosslinking degree and particle size is studied. An in vitro test is carried out to compare the performance as prolonged release preparation of a resinate, e.g. procainamide resinate, with the action of the pure drug and of a Durette formulation.

Delayed-Action Preparations↗
PubMedDate not supplied

Phosphate ion exchange resin used in the liquid preservation of baboon red cells.

Baboon whole blood, collected in 14 percent citrate-phosphate-dextrose anticoagulant solution in plastic bags was stored in 100-ml aliquots at 4 degrees C for 28 days in the presence or absence of 0.75 grams of phosphate anion exchange resin. In vitro and in vivo measurements after autologous transfusions were made to determine whether the phosphate anion exchange resin had any beneficial effect on the blood during storage. The in vitro measurements of red cell 2,3-diphosphoglycerate and P50 were higher throughout the 28 days of storage at 4 degrees C in the blood stored in the phosphate anion exchange resin. After autologous transfusions in six baboons of red cells prepared from whole blood stored at 4 degrees C for 21 days, the 24-hour posttransfusion survival values were 86 +/- 6 percent (mean +/- SD) in the presence of resin and 83 +/- 6 percent in the absence of resin. In five other baboons, red cells prepared from 28-day-old blood showed a mean 24-hour posttransfusion survival of 82 +/- 4 percent in the presence of resin and 75 +/- 4 percent in the absence of resin. The addition of a phosphate anion exchange resin to the citrate-phosphate-dextrose anticoagulant provided better maintenance of red cell 2,3-diphosphoglycerate concentrations and P50 levels during storage of whole blood at 4 degrees C, and red cells prepared from whole blood stored in this solution had better oxygen transport function than red cells prepared from blood stored without resin. Red cell adenosine triphosphate concentrations and 24-hour posttransfusion survival values were similar whether or not the anticoagulant contained resin.

Animals↗
PubMed1981

Storage of platelet concentrates using ion exchange resin charged with dibasic phosphate..

Platelet concentrates were prepared at twice the normal concentration and stored at room temperature for 7 days in either standard bags (controls) or bags to which 1 or 2 g of Amberlite resin beads charged with dibasic phosphate had been added. The resin beads served as a buffer system by providing a "slow release" form of phosphate ions as well as by binding CO2 produced during platelet metabolism. Control platelets demonstrated rapid falls in pH, ATP content, morphology score, and thrombin-induced nucleotide release after 24 hr of storage with a fall in pH to less than 6.0 by day 3. Profound ultrastructural changes and a rise in pO2, suggesting loss of platelet viability, accompanied these changes. In contrast, the resin-stored platelets remained near normal after 24 hr of storage, with preservation of discoid morphology, 95% of ATP levels, excellent ultrastructural appearance, and evidence of continued oxygen consumption after 3 days of storage. Even after 7 days of storage, ATP levels remained greater than 50% of baseline and ultrastructurally intact platelets were seen. In the 1-g resin bags the pH remained at baseline levels (6.9-7.0), while there was a rise in pH in the 2-g resin bags. These results demonstrate the beneficial effects of maintaining a higher pH during platelet storage and provide a new approach to studying the metabolic changes that occur during longer term storage.

Adenine Nucleotides↗
PubMed1987

Ion-exchange resins as potential phosphate-binding agents for renal failure patients: effect of the physicochemical properties of resins on phosphate and bile salt binding.

The effect of resin type, degree of cross-linking, bead size, and surface area on the phosphate and bile salt binding characteristics of five strongly basic Dowex anion-exchange resins in the chloride form was studied. The maximum uptake of phosphate (expressed as uptake of phosphorus) from sodium phosphate solutions was 137, 82, 86, 138, and 76 mg of phosphorus per gram of dry Dowex resins XF 43311, XY 40013, XF 43254, XY 40011, and XY 40012, respectively. The presence of simulated gastric or intestinal fluids resulted in small but insignificant alterations in phosphorus uptake by the resins. The resins all bound similar amounts of phosphorus and taurocholate (80-100% of the total phosphorus and taurocholate in solution) at physiological concentrations of phosphate and bile salt. Dowex resins XY 40013 and XF 43254, with identical physicochemical properties, but different bead sizes and surface areas, bound similar amounts of the bile salt sodium taurocholate at all taurocholate concentrations, indicating that binding was not restricted to the surface sites on the resin bead. The 2% cross-linked resins bound 3-4 times more taurocholate than the 8% cross-linked resins (at high taurocholate concentrations); the smaller pore size of the latter resins probably presents a greater mechanical exclusion barrier than the larger pore size of the 2% cross-linked resins.

Anions↗
PubMed1994

[Early forms of cerebrovascular diseases in workers in the manufacture of ion-exchange resins].

Persons with initial insufficiency of blood circulation in the brain were more frequent among workers who had professional contact with styrol than in control group. Microcirculatory disorders were established to parallel length of work in hazardous conditions and play an important role in development of initial cerebrovascular pathology. Microwave bioresonance therapy may be a secondary prophylactic measure.

Adult↗
PubMed2003

Kinetic investigation of Eu(III)-humate interactions by ion exchange resins.

The kinetic stability of radionuclides bound to aqueous colloids is a determining factor in their migration from a radioactive waste repository. The cation exchangers Chelex-100, Dowex 50Wx4, and Cellphos (cellulose phosphate) have been shown a promising tool for kinetic investigations. This study assesses the applicability of different exchange resins for Eu humate dissociation kinetics investigations. All resins were found to produce satisfactory results. A systematic study of parameters affecting the dissociation rates of Eu(III) humate complexes was performed. A set of purified humic substances was found to behave in the same way. However, unpurified Aldrich humic acid showed significant differences.

Europium↗
PubMed2004

Ion exchange resins as catalyst for the isomerization of alpha-pinene to camphene.

Camphene is an industrial intermediate compound for commercial chemicals such as isoborneol, isobornyl acetate and camphor. Industrially, the conventional process for camphene production consists of the isomerization of alpha-pinene using acidic TiO2 as catalyst. The use of this catalyst presents problems such as considerable time for preparation, reproducibility and recovery of catalyst from products after the alpha-pinene isomerization. For the first time, a commercial exchange resin was used as catalyst for this reaction. Based on the concentration of product as a function of the reaction time, the path of the alpha-pinene transformation to camphene and byproducts is proposed. Temperature and alpha-pinene/catalyst ratio were studied in order to optimize the yield to camphene production. The obtained results were comparable with those reported for acidic TiO2.

Bicyclic Monoterpenes↗