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Results for “ION EXCHANGE RESINS”

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At least 19 recordsLinked to original sources
PubMed1971

Biological ion exchanger resins. 3. Molecular interpretation of cellular ion exchange.

The cell is presented as a biological ion exchanger resin. The similarities between ion accumulating cells and ion exchanger resins are correlated. The kinetic characteristics of biological ion exchange are shown to be amenable to analysis by a model commonly used for ion exchanger resins. The theories of ion exchange equilibria currently in use with ion exchanger resins are reviewed with their suitability for adaptation to biological ion exchange in mind.

Biological Transport↗
PubMed1978

Influence of wax coatings on release rate of anions from ion-exchange resin beads.

Ion-exchange resin beads were coated with various waxes to improve and control their release. The in vitro release rates of benzoate ions from the coated-resin beads were then investigated using a rotating sieve basket technique. The dramatic differences in release rates observed with the different waxes can be discussed in terms of the wax to resin ration and the solubility characteristics of the waxes. The initial release rates can be expressed in terms of a mathematical expression previously reported for the diffusion of ions in ion-exchange resins, thereby aiding in the elucidation of the effect of the waxes on release.

Anion Exchange Resins↗
PubMed1979

Preparation and evaluation of microencapsulated ion-exchange resin beads.

Ion-exchange resin beads in the benzoate form were coated by several microencapsulation techniques to alter and improve characteristics, especially the control of drug release, of this type of drug delivery system. The most successful techniques included polymer-polymer interaction, temperature change, and nonsolvent addition. The microencapsulated beads then were studied with respect to the release rate of the organic anion to determine the effects of microencapsulation. The release rate of the organic anion could be controlled over a wide range, depending on the encapsulating material characteristics. Factors affecting the extent and rate of release as result of microencapsulation are discussed.

Benzoates↗
PubMed1988

Cationic radioisotope delivery to loose connective tissue in vivo using ion-exchange resin beads.

Ion-exchange resin beads, implanted into connective tissue, were used as the vehicle for the delivery of radiolabelled cations to determine the local distribution of lead, silver and cadmium in loose connective tissue. The system was devoid of systemic toxicity, permitted a predictable release, enabled location of released cations in respect to the site of bead implantation, afforded safety and could be used with several other cations. The radiolabels released into the tissue formed an immediate relationship with inflammatory cells and a more protracted relationship with the matrix elements of the local connective tissue. The lesion induced by the presence of the bead was complicated by the particular cation.

Animals↗
PubMed1971

Biological ion exchanger resins. II. QUERP water and ion exchange selectivity.

Biological selectivity is shown to vary with medium osmotic strength and temperature. Selectivity reversals occur at 4 degrees C and at an external osmolality of 0.800 indicating that intracellular hydration and endosolvent (intracellular water) structure are important determinants in selectivity. Magnetic resonance measurements of line width by steady-state nuclear magnetic resonance (NMR) indicate a difference in the intracellular water signal of 16 Hz between the K form and Na form of Escherichia coli, providing additional evidence that changes in the ionic composition of cells are accompanied by changes in endosolvent structure. The changes were found to be consistent with the thermodynamic and magnetic resonance properties of aqueous electrolyte solutions. Calculation of the dependence of ion-pairing forces on medium dielectric reinforces the role of endosolvent structure in determining ion exchange selectivity.

Biological Transport↗
PubMed2002

Kinetics of adsorption of Co(II) removal from water and wastewater by ion exchange resins.

The capacity of ion exchange resins, IRN77 and SKN1, for removal of cobalt from aqueous solution has been investigated under different conditions namely initial solution pH, initial metal-ion concentration, and contact time. The equilibrium data obtained in this study have been found to fit both the Langmuir and Freundlich adsorption isotherms. The adsorption of Co(II) on these resins follows first-order reversible kinetics. The film diffusion of Co(II) in these ion exchange resins was shown to be the main rate limiting step. The studies showed that these cation exchange resins can be used as efficient adsorbent material for the removal of Co(II) from aqueous solutions.

Adsorption↗
PubMed2000

Determination of glyphosate and aminomethylphosphonic acid residues in water by gas chromatography with tandem mass spectrometry after exchange ion resin purification and derivatization. Application on vegetable matrixes

An analytical method for the determination of glyphosate and its principal metabolite, aminomethylphosphonic acid (AMPA), in water of different hardnesses (5, 20, and 30 degrees DH, french hardness) has been developed. Samples were fortified at different levels (0.05, 0.1, 1, and 5 microg/L) and were purified by column chromatography on ion-exchange resins. After derivatization with TFAA/HFB mixture, the derivatives were quantified by using capillary gas chromatography with an ion-trap tandem mass spectrometric detector. Analytical conditions for MS/MS detection were optimized, and the quantification was carried out on the sum of areas of the three most representative ions: m/z 283, 223, and 181 for AMPA and m/z 440, 321, and 261 for glyphosate. The limit of quantification was demonstrated to be at 0.05 microg/L for each compound. The mean recovery value and the relative standard deviation (n = 65) were 93 and 12% for AMPA and 95 and 13% for glyphosate.

Journal Article↗
PubMedDate not supplied

[Ion exchange resins].

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Ion Exchange Resins↗
PubMed1994

A simple method for classification of antibiotics using ion exchange resins added to agar plates.

Using two different ion-exchange resins (Dowex 50W-X4 as cation and Dowex 1-X4 as anion) added directly to assay plates seeded with Bacillus subtilis or Micrococcus luteus, the size of the inhibitory zone produced by 36 antimicrobial agents around a disc or cup was characterized into various types, such as acidic, basic or amphoteric. An increase of the inhibition zone following addition of 15% Dowex 50W-X4 was evident in penicillins except for ampicillin and penicillin-G, and polyethers. Aminoglycosides, macrolides and colistin, lincomycin, and sulphonamides on assay medium treated with Dowex 1-X4 showed a similar effect on the inhibition zone. Tetracyclines, virginiamycin, oxolinic acid and furazoridone revealed no effects on the inhibition zone with either of the resins. These antibiotics could be divided into various groups on the basis of their chemical structure. This simple and rapid method may be useful for routine laboratory testing of residual antibiotics in meat.

Anion Exchange Resins↗