Elution anion exchange resins

Sublation, SPE on Cg (MeOH elution), anion exchange resin (methanolic HCl elution), and another Cg column (MeOH elution)... 

Ion-exchange separations can also be made by the use of a polymer with exchangeable anions in this case, the lanthanide or actinide elements must be initially present as complex ions (11,12). The anion-exchange resins Dowex-1 (a copolymer of styrene and divinylben2ene with quaternary ammonium groups) and Amherlite IRA-400 (a quaternary ammonium polystyrene) have been used successfully. The order of elution is often the reverse of that from cationic-exchange resins. 

Ion Excha.nge, The recovery of uranium from leach solutions using ion exchange is a very important process (42). The uranium(VI) is selectively adsorbed to an anion-exchange resin as either the anionic sulfato or carbonato complexes. In carbonate solutions, the uranyl species is thought to be the tris carbonato complex, U02(C03) 3 [24646-13-7] and from sulfate solutions the anion is likely to be U02(S0 , where nis ) [56959-61-6] or 2 [27190-85-8], The uranium is eluted from the resin with a salt or acid solution of 1 AfMCl or MNO (M = H", Na", The sulfate solution is... 

Theory. The anion exchange resin, originally in the chloride form, is converted into the nitrate form by washing with sodium nitrate solution. A concentrated solution of the chloride and bromide mixture is introduced at the top of the column. The halide ions exchange rapidly with the nitrate ions in the resin, forming a band at the top of the column. Chloride ion is more rapidly eluted from this band than bromide ion by sodium nitrate solution, so that a separation is possible. The progress of elution of the halides is followed by titrating fractions of the effluents with standard silver nitrate solution. 

Theory. Cadmium and zinc form negatively charged chloro-complexes which are absorbed by a strongly basic anion exchange resin, such as Duolite A113. The maximum absorption of cadmium and zinc is obtained in 0.12 M hydrochloric acid containing 100 g of sodium chloride per litre. The zinc is eluted quantitatively by a 2M sodium hydroxide solution containing 20 g of sodium chloride per litre, while the cadmium is retained on the resin. Finally, the cadmium is eluted... 

Anion exchange resins have been used to determine extremely low concentrations of nitrite down to nanomoles in seawater. Wada and Hattori [148] formed an azo dye from the nitrite using N-1 naphthylethylene diamine dihydrochloride and then adsorbed the dye in an anion exchange resin. The dye is then eluted from the column with 60% acetic acid and measured spec-trophotometrically at 550 nm. 

Trace amounts of molybdenum were concentrated from acidified seawater on a strongly basic anion exchange resin (Bio-Rad AG1 X-8 in the chloride form) by treating the water with sodium azide. Molybdenum (VI) complexes with azide were stripped from the resin by elution with ammonium chlo-ride/ammonium hydroxide solution (2 M/2 M). Relative standard deviations of better than 8% at levels of 10 xg per litre were attained for seawater using graphite furnace atomic absorption spectrometry. 

Copper Adsorption on basic Amberlite GC-400 anion exchange resin, elution with nitric acid AAS 0.013 pg/1 [869]... 

Molybdenum Anion exchange resin adsorption (Biorad Agl-X8), elution Graphite furnace AAS <10p,g/l... 

Rhenium Adsorption on Deacidite FF anion exchange resin, elution Neutron activation analysis 0.06 ng/1 [539]... 

Silver Silver pre-concentrated on Deacidite FF IP anion exchange resin, eluted with thiourea Neutron activation analysis < 40 ng/1 [559]... 

As mentioned in the historical synopsis (Section 5.1), Levine121 perfected the compendial partition column procedure in which aspirin in chloroform is first trapped in an immobile phase of sodium bicarbonate on a column of siliceous earth (celite) then eluted with a solution of acetic acid in chloroform and measured spectrophotometrically. This has been also used for separation in combination products.80 For the determination of salicylic acid in presence of aspirin by this method, see Section 5.61. Ion exchange columns filled with strongly or weakly basic anion exchange resin in the acetate or chloride cycle have also been used for separation of aspirin in combination products. 122 123/l2lf This has also been adapted for a student experiment.125 A Sepha-dex-G25 column has been used for the separation of aspirin from salicylic acid.126... 

Figure 11. Left elution curve of Cu from a chalcopyrite sample in HCI 7 M on anion exchange resin AG-MP1 (Marechal and Albarede 2002). The points are fitted by an error function. The small misfit of the curve from the curve for small and large fractions eluted reflects that this function is only an approximation. Right evolution of the 5 Cu values in each fraction. The curve represents the isotopic values derived from the error function model.

Hall and Hohns have found that 10 /ig of technetiiun can be separated quantitatively from as much as 50 g of molybdenum using the Amberlite IRA-400 anion exchange resin in the perchlorate form. The irradiated metal is dissolved in a NaOH/HjOj mixture and the solution passed through the column. Molybdate is removed by elution with 10% NaOH solution pertechnetate is eluted with 0.5 M NH4SCN. 

Since protein adsorption to an anion exchange resin is reversible and does not constitute a classical immobilization, the ability of the resins to retain activity under various conditions must be determined. Macrosorb KAX DEAE bound -D-glucosidase was tested with solutions of primary interest for their final application. Several batch washes of a 1% w/v slurry were required to ensure complete equilibrium elution for a given concentration, as determined from the absence of pNPG units in subsequent washes. Several salt solutions of typical fermentation media components were tested. These included 3 mM to 50 mM solutions of MgSO, KHgPO, NaQ, and sodium acetate. Also, incubations with cellulase solutions were tested to determine if the proteins present in a cellulose hydrolysis would displace the -D-glucosidase. Both of these displacement studies were carried out at 22°C and 40 C. 

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