Anion exchange resin, Bio-Rad

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. 

Anion exchange chromatography was used to separate iron from other cations. The remainder of the acid solutions were added to mini-columns (4 ml Pasteur pipettes, Fisher Scientific Co.) containing anion-exchange resin (Bio-Rad AG 1-X8). In 6 N HCl, iron is anionic (FeCl/ ) and binds to the resin. After washing with 25 ml of 6 N HCl to remove cations, iron was eluted as a cation with 0.5 N HCl. 

Peptide benzyl esters can be transesterified at room temperature with methanol or ethanol in the presence of a strong anion-exchange resin (Bio-Rad AG1-X8, OH" form). The reaction is convenient for the cleavage of peptides from the resin support in the Merrifield solid-phase peptide synthesis.3 ... 

AG1-X4 anion-exchange resin (Bio-Rad Laboratories, Melville, NY), Cl-saturated... 

A soln. of startg. hydroxamic acid in dichloromethane treated with a 20% molar excess of methyl triflate at room temp, for 48 h - intermediate nitrone hydrotriflate (Y 95%), in deuteriochloroform deprotonated with a 20% molar excess of triethylamine methyl N-(l,l-dimethylethyl)-benzenecarboximidate N-oxide (Y 85% overall). The products are relatively unstable, being converted to 1-functionalized nitrones with a variety of nucleophiles. F.e., also with ethyl triflate, and deprotonation on silica gel or with the weakly basic anion exchange resin. Bio-rad AG3-X4, s. J.A. Warshaw et al., J. Org. Chem. 54, 1736-43 (1989). 

Analytical grade anion-exchange resin (Bio-Rad, AG 1-X4, 1(X)-2(X) mesh or 2CKM00 mesh) was converted from its original chloride form to the perchlorate form by repeated equilibration with concentrated sodium perchlorate solution, first batch-wise in a beaker and finally in a column, until the effluent from the column gave a negative test for chloride. The column was then washed with distilled water to remove excess electrolyte. 

Chloride salts of the optical isomers are prepared by removing the resolving agent with anion-exchange resin. A 0.47-g sample of (-)485-asyw-as-[Co(edda)-(en)] (brcamsul) is dissolved in 10 mL of water and 4.0 g of washed Bio-Rad AG 1-X8 anion-exchange resin, 100-200 mesh. Cl form, is added. The slurry is... 

The analyzer uses a heated, high-pressure (up to 4000 psi) anion exchange column, concentration gradient elution with an aqueous acetate buffer for separation and transport of the constituents of the sample mixture, and a recording photometer for detection and quantification of the separated constituents (Fig. 6). Earlier models of this analyzer were housed in standard 24 X 24 X 63 in. cabinets (Fig. 7) however, miniaturized versions with capillary separation columns are now being used (Fig. 8). An anion exchange resin produced by Bio-Rad Laboratories (Aminex A-27) in the size range of 10-15 ju has been found to be satisfactory. 

Plutonium in this feed solution is removed by an anion exchange column process. The anion exchange resin is Dowex 1-X4, 50 to 80 mesh nitrate form, obtained from Bio-Rad Laboratories. Ferrous sulfamate is added to the solution to eliminate hexavalent plutonium, and the feed is passed through the column. The ion column effluent (ICE) contains the americium and impurities. Residual americium and impurities are washed from the column with 7M HNO3 anc t 1e was s combined with the ICE this is the feed to the bidentate process. A typical composition in g/1 is Am, 0.15 Pu, 8.2 x 10 3, Al,... 

In 1966, [Co(en)3] Bfj was separated into its optically active enantiomers on a colunm of anion-exchange resin, which was in advance loaded with tartrate or anti-monyltartrate ions. The resolution was partial. In the same year, Brubaker et al. achieved the total resolution of a trinuclear cobalt(III) complex, hexakis(2-amino-ethanethiolato)tricobalt(III) bromide on a column of a cation-exchange cellulose (Bio-Rad Cellex CM) by eluting with 0.1 mol/dm NaCl. 

Dowex anion exchange resin AG1-X8 (Bio-Rad Laboratories, Richmond, Calif.). Lanthanum carrier solution. Lanthanum nitrate was dissolved in water and purified from interfering a activity be passage through the anion exchange column after adjusting the HCl content to ION. Excess HCl was removed by evaporation and... 

Mixed bed cation/anion exchange resins (e.g., Bio-Rad AG 501) are used for desalting nonionic samples in aqueous solutions. Scott (88) has discussed desalting of blood and urine samples prior to carbohydrate TLC by this approach. Desalting of proteins (> 6000 daltons) can be done by gel filtration chromatography on Bio-Rad P-6DG polyacrylamide desalting gel. 

Macmillan and Wright describe a method suitable for trace analysis, down to levels of 0.2 ppm (90). Ion exchange is used to remove ionic material. (Three columns, 2.2 x 28.5 cm, in series one of Bio-Rad AG 50W-X8, H" form, two of a strongly basic anion exchange resin. Elution of 8 g sample is performed with 85 10 5 isopropanol/water/meth-... 

Slagt and coworkers recommend pre-concentration of sultones by either ion exchange or extraction (91). (Ion exchange 2 x 40 cm, either the mixed resin Amberlite MB-3 or the anion resin Bio Rad AG 1-X2, d form elution of 5 g sample is performed with 400 mL 80 20 methanol/methylene chloride. Extraction hexane/50 50 ethanol/water.) HPLC is performed on the residue with a mobile phase of 20 80 ethyl acetate/hexane. 

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