Optimization

Two approaches to the optimization of affinity separations can be identified. The first 'practical' approach makes use of information and experience gained from experimentation, typically at the laboratory scale. Such an approach may be expensive and time consuming and may require the availability of substantial amounts of the target biomolecule, a situation that may be highly undesirable in the early stages of the development of a product with possible therapeutic value. The second 'theoretical modelling' approach is based on the philosophy that a complete understanding of the events that occur during an affinity separation can lead to optimization being achieved by computer-based methods. Such a situation is potentially cheaper and quicker, but requires confidence that the modelling approach adopted accurately describes the true situation. Sometimes it is necessary to combine the two approaches.

In addition to optimization of the choice of affinity ligand and the materials and methods for its immobilization, which have already been described above, a number of factors have to be considered when optimizing an affinity separation. These factors, which will have an influence on each other, include:

• Choice of flow rates. It is necessary to adopt a suitable compromise between fast rates to minimize purification time and slow rates to allow mass transfer and kinetic processes to occur. The nature of the matrix material chosen for the process and its resultant mass transfer characteristics strongly influence this consideration;

• Choice of irrigating liquid. The success of washing and elution procedures depends critically on the influence the liquid has on the strength of the adsorbent/adsorbate complex, particularly in relation to its effect on complexes of other compounds adsorbed specifically or non-specifically. • Cutting the eluted peak. Most affinity separations achieve resolution and purification in the adsorption stage resulting from the specificity of the affinity ligand. However the use of 'group-specific' ligands may result in the adsorption of compounds other than the desired target. Under these circumstances attempts may be made to resolve the adsorbed species by use of a series of step changes in eluent composition and/or the use of a continuous gradient, and it is necessary to identify the portion of eluent containing the target compound. The cut may be made as a compromise between the yield and the degree of purification required.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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