Chromatography column materials

Collecting fractions during column chromatography. Column material and elution procedure are chosen to effect optimal separation of the desired protein. 

In the so-called high-performance liquid chromatography column materials with a small particle size (3-10 /im) and a narrow size distribution (- 20%) are used. 

Chromatography column materials and matrices Bio-Rad, IBF-biotechnics, Kem-en-Tec, PerSeptive Biosystems, Pharmacia, Pierce, Sigma, Spectrum, Supelco, TosoHaas Chromatography devices Bio-Rad, Gilson, Pharmacia, Supelco, TosoHaas Cross-linkers Pierce Dialysis Pierce, Spectrum... 

At the beginning, with ion chromatography, column materials utilized particles greater than 40 p.m and generated only about 120 and 300 theoretical plates efficiency. In the first commercial column used for IC (Dionex AS-1), the particle size was reduced to 25 p.m and efficiencies increased to —700 theoretical plates. Modem high-capacity columns have efficiencies over 5000 plates (for 4 X 250 mm column dimensions) and 5 p-m particle size. ... 

In the continuous process for producing phosphatidylcholine fractions with 70—96% PC at a capacity of 600 t/yr (Pig. 5) (16), lecithin is continuously extracted with ethanol at 80°C. After separation the ethanol-insoluble fraction is separated. The ethanol-soluble fraction mns into a chromatography column and is eluted with ethanol at 100°C. The phosphatidylcholine solution is concentrated and dried. The pure phosphatidylcholine is separated as dry sticky material. This material can be granulated (17). 

The advantages of monosized chromatographic supports are as follows a uniform column packing, uniform flow velocity profile, low back pressure, high resolution, and high-speed separation compared with the materials of broad size distribution. Optical micrographs of 20-p,m monosized macroporous particles and a commercial chromatography resin of size 12-28 p,m are shown in Fig. 1.4. There is a clear difference in the size distribution between the monodispersed particles and the traditional column material (87). 

FIGURE 1.4 Optical micrograph of macroporous chromatographic column materials, (a) Monosized particles of 20 tm. (b) Commercial column filling of 12-28 tm. [Reprinted from T. Ellingsen et al. (1990). Monosized stationary phases for chromatography.7. Chromawgr. 535,147-161 with kind permission from Elsevier Science-NL, Amsterdam, The Netherlands.]... 

A variety of chromatographic techniques are now in common use, all of which work on a similar principle. The mixture to be separated is dissolved in a solvent, called the mobile phase, and passed over an adsorbent material, called the stationary phase. Because different compounds adsorb to the stationary phase to different extents, they migrate along the phase at different rates and are separated as they emerge (elute) from the end of the chromatography column. 

Rapidase C-80 (Gist -brocades) was used as enzyme source. The fractionation procedure of the crude preparation included chromatography on Bio-Gel PIO (100-200 mesh), DEAE-Bio-Gel A, and Bio-Gel HTP (Bio-Rad, Richmond, CA, USA). Other column materials used were cross-linked alginate (degree of cross-linking 2.34, prepared in our laboratory). Phenyl Superose HR 5/5 and Mono Q HR 5/5 (Pharmacia Biotech, Uppsala, Sweden). 

Figure 30 shows the results of an experiment in which a solution of Q-CdS was fractionated by exclusion chromatography in a column of sephacryl-gel This column material has holes which the smaller particles penetrate and reside in for some time. The first fraction therefore contains the larger particles. The upper part of the figure shows the absorption spectrum of the starting material, and the lower part the spectra of six fractions. The first fraction has an unstructured spectrum beginning at... 

The optimum conditions for capillary chromatography of material heart cut from a packed column demand a highly sophisticated programming system. The software provided with the model 8700 provides this, allowing methods to be linked so that pre-column and analytical column separations are performed under optimum conditions. 

The relevance of LSC data to reverse osmosis stems from the physicochemical basis (adsorption equilibrium considerations) of liquid-solid chromatography (52), and the principle that the solute-solvent-membrane material (column material) Interactions governing the relative retention times of solutes in LSC are analogous to the interactions prevailing at the membrane-solution Interface under reverse osmosis conditions. The work already reported in several papers on the subject (53-58) indicate that the foregoing principle is valid, and hence LSC data offer an appropriate means of characterizing interfacial properties of membrane materials, and understanding solute separations in reverse osmosis. 

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