Separation Principle

The same principles and instrumentation apply both to preparative and to analytical separation, although a non-destructive means of identifying the separated com- 

METHOD OF IDENTIFICATION TO TELL HOW MANY COMPONENTS HAVE BEEN SEPARATED, AND HOW MUCH THERE IS OF EACH 

METHOD OF IDENTIFICATION THAT MUST NOT CHANGE THE STRUCTURES OF COMPONENTS A, B, C, D, E... AND MEANS OF COLLECTING THE SEPARATED COMPONENTS 

In general, partition of components from a solution at a solid surface provides the principle that is most often exploited (adsorption is used only very rarely), but for amino acids and peptides, which can exist in charged forms in aqueous solutions, ion-exchange and electrophoresis separation are also available. Separation on the basis of molecular size is also used. 

In adsorption chromatography, the partition coefficient JC describes the distribution of the analyte between the stationary and mobile phases  

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H. Axelsson, Centrifugal Separations—Principles and Techniques, Alfa Laval Separation, Tumba, Sweden, presented at the Bioprocess Technology Program, University of Virginia, Charlottesville, Va., Oct. 17—25 1991. 

Separation method Characteristic properties Separation principle Separation agent Industrial appHcation... 

C.E. Meloan, Chemical Separations, Principles, Techniques and Experiments, J. Wiley Sons, New York, 2000, ISBN 0471351970. 

The evolution of media covering aqueous and nonaqueous systems on the one hand and analytical as well as microscale and macroscale preparative applications on the other hand has resulted in an arbitrarily nomenclature within the field. Thus the current practice is to refer to the separation principle based on solute size as size exclusion chromatography (SEC) whereas the application in aqueous systems is traditionally referred to as gel filtration (GF) and the application in nonaqueous systems is designated gel-permeation... 

It is through observing examples of actual applications that the best understanding of GC-GC separation principles can be achieved. Over the past 30 years, there have been essentially three main areas where two-dimensional gas chromatography has been applied ... 

Fig. 4 Coupling the separation principles of adsorption and partition chromatography.

C. E. Meloan, Chemical Separations Principles, Techniques Experiments, Wiley-Interscience, New York, NY (2000). 

A purification procedure including all of the separation principles then known led to a 156-fold purification of exopectate lyase of Clostridium multifermentans, but pectinesterase could not be re-moved.51,105... 

Fig. 17.14. Separation principle in MECC. A compound (neutral or charged) is partitioned between the micellar and aqueous phase. A fully solubilized neutral compound migrates with the velocity of the micelles. A neutral compound with no affinity for the micelles migrates with the velocity of the EOF. A neutral compound with an affinity for both the micellar and the aqueous phase migrates with an intermediate velocity. (A) Schematic overview of the partitioning of compound (N the EOF moves toward the cathode and the typical SDS micelles toward the anode. (B) Diagram of the zone distribution within the capillary. (C) Reconstructed typical electropherogram.

CE provides analysis based on orthogonal separation principles compared to other techniques as well as high resolving power. Like slab gel electrophoresis, CE is a family of techniques that resolve sample components by differences in intrinsic molecular characteristics such as size, mass, charge, differential interaction, and isoelectric point (pi). 

CE is frequently compared to two of the mainstream techniques in the protein laboratory HPLC and gel electrophoresis. The comparison to HPLC focuses on the instrumentation format and modes of detection, whereas gel electrophoresis shares its separation principles with CE. CE exploits the same molecular differences of the sample components to achieve separation as slab gel... 

In CZE, the capillary, inlet reservoir, and outlet reservoir are filled with the same electrolyte solution. This solution is variously termed background electrolyte, analysis buffer, or run buffer. In CZE, the sample is injected at the inlet end of the capillary, and components migrate toward the detection point according to their mass-to-charge ratio by the electrophoretic mobility and separations principles outlined in the preceding text. It is the simplest form of CE and the most widely used, particularly for protein separations. CZE is described in Capillary Zone Electrophoresis. ... 

If all the state variables are not measured, an observer should be implemented. In the Figure 14, the jacket temperature is assumed as not measured, but it can be easily estimated by the rest of inputs and outputs and based on the separation principle, the observer and the control can be calculated independently. In this structure, the observer block will provide the missing output, the integrators block will integrate the concentration and temperature errors and, these three variables, together with the directly measured, will input the state feedback (static) control law, K. Details about the design of these blocks can be found in the cited references. 

Type Phase A Phase B Separation Principle Phase A Phase B... 

Adsorption on polar stationary phases is the oldest separation principle applied in column chromatography. The chromatographic process is... 

The electrophoretic separation principle is based on the velocity differences of charged solute species moving in an applied electric field. The direction and velocity of that movement are determined by the sum of two vector components, the migration and the electroosmotic flow (EOF). The solute velocity v is represented as the product of the electric field strength E and the sum of ionic mobility uUm and EOF coefficient /a OF ... 

Fig. 1 Schematic representation of the separation principle of MEKC. An EOF/ micelle marker and three solutes differing in lipophilicity in the presence of anionic micelles in the background buffer are present. The lipophilicity increases in the sequence Sj < S2 < S3 t—migration time of EOF (nonionic solutes) S (solute) me —micelle.

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