Hassan Rezadoost

2. Definition Scale-up Overloading Effects in preparative LC Preparative Chromatography Apparatus Application

3. the amount of material that is separated does not necessarily determine whether the separation can be classed as preparative or not. all preparative separations involve the actual collection of an eluted component and does not merely comprise peak profile monitoring for quantitative estimation and elution time measurement.

4. THEORETICAL CONSIDERATIONS IN SCALE-UP In order to have a successful scale-up it is desirable to maintain kinetic (particle size, pore size, ligand chemistry, temperature, mobile phase) and dynamic (bed height, flow velocity, packing density) equivalence between the chromatography columns used in the laboratory and the pilot plant. This objective can be accomplished by using identical stationary and mobile phases in the two columns and operating them at identical bed height, linear flow velocity, protein loading (mg protein per mL of resin), feed conditions, gradient length, and gradient slope. the most common procedure used to increasecolumn volume is to increase the column diameter so that the column volume increases proportionatel.

6. A typical scale-up from laboratory to pilot plant is on the order of 50�100-fold. This is frequently followed by a 10�50-fold scale-up from pilot plant to final commercial manufacturing scale. The usual approach is to hold the plate count constant upon scale-up and increase the feed volume and column volume proportionately. This approach was originally based on the assumption of linear adsorption.

7. column loads were increased for preparative purposes by increasing the dimensions of the column both in GC and in HPLC. However, this approach has distinct limitations.

8. If the column radius is increased, unless special packing techniques are employed, the packing procedure becomes inefficient and the packing itself unstable. In addition to maintain the optimum mobile phase velocity, the flow rate will need to be substantially increased and the consumption of mobile phase will eventually become economically impractical. if the column length is increased, then the impedance to flow will become greater leading to high column pressures. lengthening the column will eventually require the particle diameter to be increased to provide adequate permeability. Increased particle diameter will, in turn, reduce the column efficiency

11. One of the limiting factors that controls the throughput of the preparative chromatograph will be the maximum permissible sample volume. The maximum sample volume is that volume that will limit any loss of resolution to an acceptable and pre-defined level. The Maximum Sample Volume

12. Sample Volume Overload

16. Sample Mass Overload

18. It is also clear that in chromatography, column over load is a very effective way of increasing the throughput and by adjusting the selectivity (using temperature, selected stationary phases, or gradient elution) very large sample loads can be tolerated. This approach should always be considered first for moderate loads before contemplating large scale column design.

19. Preparative Chromatography Apparatus

20. Preparative Columns

21. Packing Preparative Columns

25. Preparative Detectors 

26. Recycling Development

28. Improving loadability

43. The effect of Column diameter( column diameter is a crucial parameter for efficient preparative separations)

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