Ion exchange resin Bio-Rad

Dichlorodibenzo- -dioxin. 2-Bromo-4-chlorophenol (31 grams, 0.15 mole) and solid potassium hydroxide (8.4 grams, 0.13 mole) were dissolved in methanol and evaporated to dryness under reduced pressure. The residue was mixed with 50 ml of bEEE, 0.5 ml of ethylene diacetate, and 200 mg of copper catalyst. The turbid mixture was stirred and heated at 200°C for 15 hours. Cooling produced a thick slurry which was transferred into the 500-ml reservoir of a liquid chromatographic column (1.5 X 25 cm) packed with acetate ion exchange resin (Bio-Rad, AG1-X2, 200-400 mesh). The product was eluted from the column with 3 liters of chloroform. After evaporation, the residue was heated at 170°C/2 mm for 14 hours in a 300-cc Nestor-Faust sublimer. The identity of the sublimed product (14 grams, 74% yield) was confirmed by mass spectrometry and x-ray diffraction. Product purity was estimated at 99- -% by GLC (electron capture detector). 

Deionized formamide- Mix 5.0 g mixed-bed ion-exchange resin (Bio-Rad [Hercules, CA] AG501-x8,20-50 mesh) with 50 mL formamide. Stir for 45 mm, and filter with Whatman s filter paper. Store in aliquots at-20°C... 

Method. Solutions of amino acids in phosphate buffer (pH 9.3) are mixed with an equal volume of freshly prepared 0.4 M pyridoxal solution (adjusted to pH 9.3) and permitted to stand at 8 °C for 30 min. (The molar ratio of pyridoxal to amino acid should be >75 1.) At this point, 1 ml of sodium tetrahydroborate solution (100 mg/ml in 0.1 N sodium hydroxide) is added and the contents are gently shaken. Excess of sodium tetrahydroborate is destroyed by addition of sufficient hydrochloric acid (pH 1-2) prior to column chromatography. The pyridoxal derivatives are separated on a column (100 X 0.6 cm) of Aminex A-5 ion-exchange resin (Bio-Rad) at a mobile phase flow-rate of 33 ml/h. The eluting solvents consist of 0.2 N buffers at pH 3.40,4.44 and 4.86 and a 0.35 N buffer at pH 5.86 (all of the buffers are sodium citrate). The separation of a number of pyridoxyl-... 

Deionized formamide Mix 5 g of mixed bed ion-exchange resin (Bio-Rad AG501-x8, 20-50 mesh) with 50 mL of formamide. 

The ion-retardation resin Bio-Rad 11A8 (Bio-Rad Laboratories) is often used to desalt samples prior to amino acid TLC (Heathcote, 1979). A list of suggested ion-exchange resins for desalting blood and urine samples prior to carbohydrate TLC is presented in Scott (1969). A desalting procedure used prior to amino acid TLC that does not involve resin columns, but instead uses acidified butanone, is given in Heathcote (1979). A convenient method for desalting samples prior to carbohydrate TLC is by preferential extraction of carbohydrates with pyridine as described in Scott (1969). 

A primary amine, protected by reaction of the amine with cyclopentadiene and formaldehyde (H2O, rt, 3 h), is cleaved by trapping cyclopentadiene with A -methylmaleimide (H2O, 2.5 h, 23-50°, 61-97% yield), CUSO4 (EtOH or MeOH, 70°, 74-99%), or Bio-Rad AG 50W-X2 acid ion-exchange resin, 82-98% yield. ... 

New types of ion exchange resins have also been developed to meet the specific needs of high-performance liquid chromatography (HPLC) (Chapter 8). These include pellicular resins and microparticle packings (e.g. the Aminex-type resins produced by Bio-Rad). A review of the care, use and application of the various ion exchange packings available for HPLC is given in Ref. 19. 

The checkers used analytical grade AG 50W-X8 resin, which is a strongly acidic polystyrene gel type resin, supplied by Bio-Rad Laboratories. The submitters used the large-pore, strongly acidic ion-exchange resin Lewatit SPC 118, supplied by Bayer AG. 

Hollander and co-workers [303—305] dealt with the problem in detail and developed a method for the isolation of hormones from blood, using Bio-Rad AG 50W-X2 (100—120 mesh) ion-exchange resin. Acylation with pivalic anhydride—methanol—triethylamine (20 1 1) was performed at 70°C for 10 min. The derivatives were purified with the aid of Amberlite IR-45 resin and benzene as a solvent. The dry residue was dissolved in 100 jul of benzene and 5 /il were injected directly on to a 60 cm X 4 mm I.D. column packed with 5% OV-1 on Chromosorb W HP after an isothermal period at 220°C for 12 min, the temperature was increased at 3°C/min up to 300°C. Calibration standards were injected immediately after the sample. Almost identical results were obtained for T3 by GC and radioimmunoassay [304], Other workers [306] applied the same procedure to the seeds and analysed pivalyl methyl esters of T3 and T4 on an 81 cm column packed with 3% of Dexsil on Chromosorb W HP at 305°C. 

Hybridization Procedure. Formamide is deionized by adding 1 g of mixed bed ion-exchange resin (e.g., AG 501-X8, Bio Rad, Hercules, CA) to 10 ml of formamide, which is stirred on a magnetic stirrer for at least 1 hr and then filtered twice through filter paper. Store at —20°. Prehybridize filters in the above buffer for 4-8 hr at 45°, replace the solution with fresh... 

Formamide is deionized by sdrring for 30 min with 10% (w/v) of a mixed-bed ion exchange resin (e.g., Bio-Rad AG 501-X8,20-50 mesh, Bio-Rad, Richmond, CA), filtering twice through Whatman (Clifton, NJ) no. 1 paper and storing single-use aliquots at -80°C. 

Bl. Bio-Rad Laboratories, Price List U. Ion Exchange Resins and Systems, p. 20, Richmond, Calif., 1969. 

M 630.89, m 184-196°, [a]g + 19 (c 2, H2O), pKEst(i) <2 (acidic), pKEst(2) 9 (basic). Dissolve this zwitterionic detergent ( 60g) in 40% aqueous MeOH and stir it with the mixed-bed ion-exchange resin RG-501 x 8 (lOOg, Bio-Rad) until the pH of the supernatant is 7. Filter off the resin and evaporate the filtrate to dryness under reduced pressure. Check for homogeneity by TLC on silica gel G in 95% MeOH/5% NH4OH and visualize the spot with iodine vapour (see CHAPS above). [Hjelmeland et al. Anal Biochem 130 72 1983, Matuo et al. Methods Enzymol 198 155 1991.]... 

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. 

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