Chromatography recycle

Quinones, I., Grill, C.M., Miller, L., and Guiochon, G., Modeling of separations by closed-loop steady-state recycling chromatography of a racemic pharmaceutical intermediate,. Chromatogr. A, 867, 1, 2000. 

Figure 23-14 Separation of 0.5 mM L-phenylalanine and 0.5 mM L-phenylalanine-D5 by repeated passes through a pair of Hypersil C8 liquid chromatography columns (25 cm x 4.6 mm) eluted with 10 90 acetonitrile water containing 25 mM Na2SOA and 0.1% trifluoroacetlc acid in the water. [FromK.Lan and J. W. Jorgensen,"Pressure-Induced Retention Variations In Reversed-Phase Alternate-Pumping Recycle Chromatography," Anal. Chem. 1998, 70,2773.]...

Figure 5.6 Schematic design for recycling chromatography in which the effluent is recycled through the pump 1, eluent 2, pump 3, injector 4, chromatographic column 5, detector 6, three way valve 7, waste 8, T-connection.

H. Kalasz, Peak and cycle capacity of recycling chromatography , Chromatographia 20 125-128(1985). 

J. Dingenen and J. N. Kinkel, Preparative chromatographic resolution of racemates on chiral stationary phases on laboratory and production scales by closed-loop recycling chromatography , J. Chromatogr. 666 627 -650 (1994). 

Multidimensional chromatography has been called column switching, coupled-column chromatography, recycle chromatography, and mode sequencing, among other terms. 

Using the efficiency of the column to your advantage Calculation of efficiency Proper choice of flow rate Comparison of efficiencies of columns Recycle chromatography Analytical recycle Preparative recycle... 

FIGURE 6-7. Recycle Chromatography, (a) Schematic. (b) Example of a recycle valve. 

In summary, recycle results in increased throughput, reduced separation time, lower solvent consumption, and complete recovery of the compounds (if desired) in the preparation mode. Chapter 10 (Experiment 3) contains an experiment that illustrates the basic experimental techniques of accomplishing recycle chromatography. 

To determine the influence of column length upon the number of theoretical plates and upon resolution and to demonstrate the ability of increased resolution through utilization of recycle chromatography. 

Theoretical treatments on recycling chromatography have been published by Chizhkov [67], Martin [68], and Coq [69]. Seidel-Morgenstern and Guiochon [70] developed a mathematical model to design recycling and... 

SEPARATION OF ACANTHOSIDE-D IN ACANTHOPANAXSENTICOSVS BY PREPARATIVE RECYCLE CHROMATOGRAPHY... 

Closed-loop recycling chromatography (reviewed by Dingenen and Kinkel 422)) may be necessary for separations of compt)unds with low enantioselectivity. 

Olefins Aromatics. The hydroboration and analysis of shale oil distillate fractions have been described previously (9). Whole shale oils were prepared for determination of olefin and aromatic content by the removal of the polar material on Florisil (30/60 mesh, used as received) by elution with cyclohexane. The Florisil-to-oil weight ratio was 20/1 and the elution was carried out for 24 hr with a solvent recycle chromatography column. 

Chersi, A. The purification of lactic dehydrogenase by recycling chromatography. Sci. Tools [Stockholm] 11, 1 (1964). 

Porath, J., and H. Bennich Recycling Chromatography. Arch. Biochem. Biophysics Suppl. 1, 152 (1962). 

The critical point in closed-loop recycling chromatography is the increase in axial dispersion due to the additional hold-up volume generated by the pump head and... 

Fig. 5.9 Closed-loop recycling chromatography with peak shaving.

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