Cation-exchange resin columns

Radium in hydrochloric acid solution may be separated effectively by ion exchange methods using cation exchange-resin columns. A weak HCl solution is passed through the column. The absorbed metals on the ion-exchange column are eluted with ethylenediaminetetraacetic acid (EDTA) at pH 6.25 or with ammonium citrate at pH 7.8. With either eluant, radium is eluted last, after removing barium and then lanthanum, calcium, magnesium, and other metals. 

A cation exchange resin column is saturated with copper(II) ions recovered from rinse waters from plating operations. 

Amino acids can be separated without prior derivatization on a cation-exchange resin column. The elution buffers are classically lithium citrate buffers with different pH values and salt concentrations, which are applied stepwise. There is usually a programmed increase in column temperature. Consequently, there are numerous variables affecting the separation of the individual amino acids [6]. For the detection of the amino acids, the column effluent is mixed with the ninhydrin reagent. Nowadays there are only very few manufacturers of AAAs left. The considerable cost of purchase and the operation costs are a potential threat to the widespread application of this technique, although it is still considered to be the definitive method for diagnosing disorders of amino acid metabolism. 

Polyaminepak (strong cation-exchange resin) column. 

For demineralization, a set of strong-acid and weak-acid cation-exchange resin columns, and strong-base anion-exchange and weak-base ion-exchange resin columns have been applied [6],... 

You have been asked to design a cation-exchange resin column to remove 10 meq L 1 Cu2+ from a given water. Calculate the size of the column, assuming that the CEC of the resin is 250 meq/100 g, its density 1.5 g cm-3, and the amount of water to be treated is 10,000 L per month per single column. 

In those esses where complete Identification la desirable, rttre earth separations, are made using a cation exchange resin column (Dowex-50, citrate elution at pi 3.5) and elevated temperature as described by Thompson et al., as follows ... 

Chromatography on Cation Exchange Resin. The sample of acid-free asphalt in benzene solution was charged into the cation exchange resin column prewet with benzene. The size of the column, the temperature, and the ratio of the sample to the resin were the same as in the anion exchange chromatography step. Unreactive material was washed from the resin with benzene for approximately 24 h. The reactive compounds (bases) were recovered as two subfractions, the first eluted with methanol-8 percent isopropylamine for 6 h and the second with trichloroethylene for 6 h. The two base subfractions were then combined for further study. 

The process of separation and quantitation of amino acids has been automated. In one automated method, a single cation exchange resin column separates all the amino acids in the protein hydrolysate. The analyzer is capable of detecting as little as 1-2 nmol of an amino acid and a complete analysis can be obtained in about 4 hours. In newer procedures, the complete analysis can be performed in about Ihour and permit detection of as little as 1-2 nmol of an amino acid. Picomole amounts of amino acids can be determined when the separated amino acids are coupled to fluorescent reagents such as o-phthalaldehyde. Amino acid separation and quantitation can also be accomplished by reverse-phase high-pressure liquid chromatography of amino acid derivatives—a rapid and sensitive procedure. 

Procedure Pass 10 ml of urine through a cation-exchange resin column (Dowex 60-W-X4, 20-50 mesh, in the hydrogen form) and wash the column with 30 ml of distilled water. Elute the amino acids with 20 ml of concentrated ammonia solution. Evaporate this eluate to dryness in vacuo. To the residue add 1 ml of trifluoroacetic anhydride and 0.5 ml of trifluoroacetic acid, and allow the mixture to stand at room temperature for 20 minutes. Remove excess reagents with a stream of air and treat the oily residue with an ethereal solution of distilled diazomethane (DANGER Poisonous-explosive) for 15 minutes. Remove excess diazomethane (CAUTION ) with a stream of air. Dissolve the residue in methanol and inject a suitable aliquot part into the gas chromatograph. Figures 25 and 26 show results obtained by this procedure. 

Figure 6.18 Complete and effective demineralization of whey by electrodialysis in combination with ion exchange resins (after softening the whey with a cation exchange resin column, electrodialysis is performed to complete removal of the minerals economically).

Ohta, K., Ohashi, M., Jin, J. Y., Takeuchi, T., Fujimoto, C., Choi, S. H., Ryoo, J. J., and Lee, K. P., Separation of aliphatic carboxyhc acids and benzenecarboxyhc acids by ion-exclusion chromatography with various cation-exchange resin columns and sulfuric acid eluent, J. Chromatogr. A, 991, 117-125, 2003. 

Tanaka, K., Ohta, K., Fritz, J. S., Lee, Y. S., and Shim, A. B., Ion-exclusion chromatography with conductimetric detection of aliphatic carboxyhc acids on an H -form cation-exchange resin column by elution with polyols and sugars, J. Chromatogr. A, 706, 385-393, 1995. 

Yamamoto et al. (1982) developed a quantitative method for the determination of putrescine, cadaverine, spermidine, and spermine in foods. Separation of the amines from foods was achieved by eluting through a cation-exchange resin column and then converted to their (ethyloxy) carbonyl derivatives by the reaction with ethyl chloroformate in aqueous medium before application to the gas chromatograph with a flame ionization detector. They used 1,8-diaminooctane as an internal standard and performed the separation and determination of the resulting derivatives on a 1.5% SE-30/0.3% SP-1000 on Uniport HP column (0.5 m) under the temperature-programmed condition. Staruszkiewicz and Bond (1981) developed a GLC procedure for the quantitative determination of the diamines putrescine... 

Cs is collected from larger volumes of water on large cation-exchange resin columns. Anion-exchange resin columns loaded with one of the above-cited precipitation reagents make these columns specific for cesium. A column loaded with... 

Soon after the discovery of element 104, Silva et al. (1970) studied its solution chemistry for the known isotope 75-s 261Rf. Positive identification was made by measuring its known half-life and decay characteristics. Several hundred elutions with a-hydroxyisobutyrate solutions from cation exchange resin columns were performed to compare the behavior of 261Rf with those of No2+, trivalent actinides, Hf4"1", and Zr4+. The behavior of Rf was similar to those of Zr and Hf, which did not sorb on the column and entirely different fromNo2+ and the trivalent actinides that did sorb on the column at pH 4.0. These studies showed unequivocally that Rf should be placed under Zr and Hf in the periodic table. 

S HyperD F cation exchange resin/column Pall Life Sciences 15 mL disposable column (Qiagen or Thermofisher)... 

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