Traditional chromatography

Using supercritical fluids rather than traditional chromatography to reduce solvent and energy use and... 

High-performance liquid chromatography (HPLC) and fast protein liquid chromatography (FPLC) rely on the same separation principles as the traditional chromatography columns, but tend to be much faster because of high flow rates that are possible due to the uniform bead size and the mechanical strength of the beads. See also Chapter 4, section 1.2.2. 

IMS can be combined with gas chromatography to give much more reliable detection. Since the separation of chemicals takes time when traditional chromatography is applied, response time becomes a problem. Fast GC, as described above, may be a means to get around this problem. However, IMS does not appear to be a useful detector for fast GC because it is limited to a simple Faraday cup detector by the presence of gas at atmospheric pressure. This... 

One strives to achieve a uniform distribution across the entire membrane surface. Again, like traditional chromatography, the dead volume must be minimized. The design of the standard dead-end filtration does not minimize the hold-up volumes in the inlet or outlet channels. The commonly available Luer-Lok connector for ease of use is one of the biggest contributors to housing related dispersion in the small syringe-type devices since the gap... 

MA systems can easily add a module to increase membrane capacity or resolution. Alternatively, the series addition of a traditional chromatography column for improvement of capacity or resolution is seldom practiced. Thus, membrane chromatography offers the chromatographer a new flexibility of easy expansion of inadequate systems. Alternatively, the easy connectibility also enables a simple way to couple multiple units of different chemistries for a mixed-mode separation.43 The next section describes these configurations in greater details. 

Two other problems often arise following the use of HPLC for purification. The first has to do with the volume of the sample used for assaying activity. Upon successful completion of the ion-exchange step, it is necessary to determine enzymatic activity. These determinations are performed on samples taken from a series collected during the course of the purification. With HPLC purification, however, the volume of each sample collected will probably be no more than a few hundred microliters, and often less. Further, the number of samples is usually small. This situation in HPLC is in contrast to that found in traditional chromatography, where the volume of each sample can be in the milliliter range and the total number of samples or fractions collected can be in the hundreds. 

A sizable financial outlay may be necessary to purchase chromatography equipment for use on scale. Equipment expenses for SMB are greater than for traditional chromatography due to the need to purchase multiple pumps and control... 

Due to these early advantages, chromatography membranes were launched in the early 1990s. Unfortunately due to their limited capacity versus chromatography media as well as their lack of capacity at high salt they did not achieve significant market penetration versus traditional chromatography media (<10%). 

A, Eddy diffusion B, Longitudinal diffusion C, Mass transfer Traditional chromatography... 

Adsorptive separations can be exemplified by the monolith system. Macroporous monoliths are stationary phases that can be prepared in a variety of shapes and dimensions using relatively straightforward polymerization chemistry and which can be derivatized with traditional chromatography ligands. ... 

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