Anion-exchange adsorption

Purification of Antibiotic 66-40 — Dissolve 28 g of crude Antibiotic 66-40 in 100 ml of distilled water and charge to an anion exchange adsorption column (Dowex 1 X2) in the hydroxyl form. Slurry 2,000 g of the resin in water in to a column 2yj in diameter and 36 "high. Elute the column with distilled water at a rate of about 23 ml/min collecting 100 ml fractions and monitor with a conductivity meter and by disc testing against Staphylococcus aureus. 

An example of an expanded bed process for recovery of a Pseudomonas exotoxin from an E. coli system has been recently reported in pilot plant scale.28 A single-step recovery of a secreted recombinant protein has been carried out in expanded-bed mode directly from the fermentation broth without prior cell removal. The fusion protein was designed to have relatively low isoelectric point to enable anionic exchange adsorption at pH 5.5 where most of the E. coli host proteins are not adsorbed. The gene product was secreted to the culture medium of E. coli in high yield and the recovery of the protein was 90% in one step.29... 

Anion-exchange adsorption behavior of ten metal ions in mixtures of HCl and HCIO4 was studied By forced-flow chromatography and automatic UV detection of the eluent stream trace amounts could be determined ... 

Second, the GMA-grafted hollow fiber was immersed in 50 (v/v)% aqueous solution of diethylamine at 303 K for 1 h and subsequently in ethanolamine at 303 K for 6 h. Sixty mole% of the epoxy groups was converted to diethylamino groups to enhance the anion-exchange adsorption of the enzyme, and subsequently, ethanolamine was added to the remaining epoxy groups to reduce the nonselective adsorption of proteins. The resultant hollow fiber was referred to as a DEA-EA fiber. 

Pietrzyk, D. Iskandarani, Z. Schmitt, G. Anion-exchange adsorption on low capacity anion exchangers Separation of organic acids, amino acids, small chain peptides. J. Liquid Chromatogr. Relat. Technol. 1986, 9 (12), 2633-2659. 

Another example of vims clearance is for IgM human antibodies derived from human B lymphocyte cell lines where the steps are precipitation, size exclusion using nucleases, and anion-exchange chromatography (24). A second sequence consists of cation-exchange, hydroxylapatite, and immunoaffinity chromatographies. Each three-step sequence utilizes steps based on different properties. The first sequence employs solubiUty, size, and anion selectivity the second sequence is based on cation selectivity, adsorption, and selective recognition based on an anti-u chain IgG (24). 

Research has shown that ascorbic acid can be produced from hulls of immature walnuts by extracting the hull with 0.2% sulfur dioxide solutions, and purifyiag the extract by adsorption on and elution from anion-exchange resias (see Ion exchange). Eluates from the anion-exchange step are concentrated, purified by organic solvent fractionations, decolorized, and crystallized (35). 

Last time development of methods of iodine determination, which include preliminary sorption preconcentration of microcomponents and their subsequent determination in phase of concentrate get great practical significance. Silica gel (SG) with adsorptively modified quaternary ammonium salts (QAS) gets properties of anion-exchange resin. The sorbents modified in this way can be used successfully for determination of different anions. 

Hydrated alumina is one of the most widespread hydrophilic polar sorbents for concentration and separation of different substances. In water Al Oj shows cation or anion exchange properties and its protolytic and adsorption characteristics depend on a way of obtaining. 

Siiica S1O2 Scale in boilers and cooling water systems Insoluble turbine blade deposits due to silica vaporization Hot process removal with magnesium salts adsorption by highly basic anion exchange resins, in conjunction with demineralization distillation... 

In order to obtain paromomycin In free base form, the hydrochloride is dissolved in water as a 3% solution, the solution Is poured into an adsorption column containing an anion exchange resin (Amberlite IR-45 or preferably IRA-411 or IRA-400) in the hydroxyl form and the column is washed with a small amount of water. 

Highly active catalysts have been produced by adsorption of lipases onto macroporous acrylate beads, polypropylene particles and phenol-formaldehyde weak anion exchange resins. Protein is bound, presumably essentially as a monolayer, within the pores of the particles. The large surface area of the particles (10m2 g 1) means that substantial amounts of protein can be adsorbed, and the pores are of sufficient size to allow easy access of reactants to this adsorbed protein. 

Dried shrimp was ground, defatted with benzene, and then extracted with cold water. The luciferase extracted was purified first by a batch adsorption onto DEAE cellulose (elution with 0.4 M NaCl), followed by gel filtration on a column of Sephadex G-150, anion-exchange chromatography on a column of DEAE-cellulose (gradient elution 0.05-0.5 M NaCl), and gel filtration on a column of Ultrogel AcA 34. The specific activity of the purified luciferase was 1.7 x 1015 photons s 1 mg-1, and the yield in terms of luciferase activity was about 28%. 

Where MU water silica is high (say, more than 20-30 ppm Si02), action probably is needed to reduce the silica level at source. This may be achieved in several ways, for example, by the use of anion exchange or flocculation-adsorption processes using ferric sulfate or magnesium hydroxide. 

The analytical methods for a-sulfo fatty acid esters reported in the literature deal with the determination of the surfactants in different matrices like detergents or product mixtures from the fabrication. The methyl esters of a-sulfo fatty acids can be separated from a mixture of different surfactants together with sulfonated surfactants by adsorption on an anionic exchanger resin such as Dowex 1X2 or 1X8. Desorption from the exchanger resin is successful with sodium hydroxide (2%) in a 1 1 mixture of isopropanol and water [105]. 

The adsorption process, in principle, is an anion-exchange process which is restricted only to the surface of the activated charcoal. This fact makes the loading or the exchange capacity of activated charcoal to be relatively smaller in comparison with ion-exchange resins, and it is for this reason that charcoals are quite often treated suitably to improve their loading capacities. The surface and the pore structure characteristics of activated carbon are the important factors upon which its industrial applications depend. 

---