Countercurrent chromatogram

Fig. 1 shows a countercurrent chromatogram of bacitracin components using the chloroform/ethanol/meth-anol/water (5 3 3 4) system. A 50-mg amount of the bacitracin complex was loaded into the HSCCC column. The retention of the stationary phase was 72.7% and the elution time was about 3 hr. All components were eluted in an increasing order of their partition coefficients, yielding 5.5 mg of pure BC-A and 1.5 mg of pure BC-F. 

The relationship between K and the cc chromatogram can be discerned visually from Figure 11-10. The universal chromatogram shows the elution of hypothetical solutes with = 0, 1,2, and 3. When K = 0, the solute spends no time in the stationary phase and emerges as the mobile phase front, V ,. Any solute with K = 1 emerges at the column volume, V. . Note that this is the focal point of the countercurrent chromatogram and is independent of the phase volume ratio. This follows directly from the retention equation when /f = 1, + F, = V. . Solutes... 

A typical countercurrent chromatogram of an alkaloid extract from endophyte-infected tall fescue seed is shown in Figure 3. Two curves are superimposed the solid line represents mg of loline-t)rpe alkaloids determined by GC analysis, and the dotted line represents absorbencies at 312 nm, which is characteristic of... 

Countercurrent Chromatogram of an Alkaloid Concentrate from Endophyte-Infected Tall Fescue, with CHCl3/MeOH/H20 (5 4 3) Lower Phase Mobile. 

Figure 4.1. Countercurrent Chromatogram of Loline Alkaloids N-methylloline (8, 61 mg), iV-acetylloline (6, 305 mg), and N-formylloline (9, 601 mg).

Figure 1. Chromatogram of fractions from countercurrent distribution of basic portion of barley extract...

Fig. 1 Chromatograms of hesperetin (1), kaempferol (2), and quercetin (3) by different countercurrent chromatographic methods. Solvent system chloroform-methanol-water (33 40 27). (A) DCCC (B) RLCC (C) multilayer coil CPC system and (D) cartridge CPC system. (Elsevier Science Ireland, Ltd.)...

Isolation and purification of individual carotenoids has been accomplished with countercurrent distribution, but the most important technique is separation by column chromatography. Two types of separation have been commonly employed. In zonal chromatography, carotenoids are applied to a column of a suitable adsorbent and then separated through development of the chromatogram with an appropriate solvent. The packing material of the column is then extruded, and the bands are scraped separately into beakers... 

Countercurrent Distribution (CCD) has been used for two decades to separate and identify steroids. Advantages of the technique include (1) mildness in treatment of compounds, dictated only by the solvent ust d, since there are no supports or adsorbants to cause possible chemical alteration (2) minimal danger of irreversible adsorption, such as occurs on columns or paper chromatograms (Neher, 1964) and (3) under ideal conditions rigorous adherence to a mathematical model, viz., the binomial distribution. Disadvantages of CCD include (1) susceptibility to emulrions, (2) tediousness of manipulation, and (3) low resolving power. 

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