Separation chromatographic column

Note that proteolysis in conjunction with ion-exchangers may be used in special cases. The pH used with anion exchangers (typically around 8) may induce the activation of proteases such as trypsin-like proteases as well as plasmin and kallikrein when traces are present (these come from animal sera). In this case DEAE and Q, ion-exchangers should therefore be avoided as the first separation chromatographic column. 

The countercurrent movement of the mobile and stationary phases is simulated in the following way the stationary phase is divided into several separate chromatographic columns which are connected in a cyclic series. Each column head is equipped with valves that allow the addition of eluent, feed and removal of the raffinate and extract from both component lines. The inlet and outlet lines will be shifted after a given time from one column to a subsequent column in the direction of the mobile phase, thus simulating the movement of the stationary phase in the opposite direction. After a complete cycle, the four lines reach their initial position. The technological parameters for running the SMB system under optimal conditions can be calculated by the available software, based on several analytical runs. 

Membrane Separators Chromatographic Columns Flow Reactors... 

This type of analysis requires several chromatographic columns and detectors. Hydrocarbons are measured with the aid of a flame ionization detector FID, while the other gases are analyzed using a katharometer. A large number of combinations of columns is possible considering the commutations between columns and, potentially, backflushing of the carrier gas. As an example, the hydrocarbons can be separated by a column packed with silicone or alumina while O2, N2 and CO will require a molecular sieve column. H2S is a special case because this gas is fixed irreversibly on a number of chromatographic supports. Its separation can be achieved on certain kinds of supports such as Porapak which are styrene-divinylbenzene copolymers. This type of phase is also used to analyze CO2 and water. 

A chromatographic column provides a location for physically retaining the stationary phase. The column s construction also influences the amount of sample that can be handled, the efficiency of the separation, the number of analytes that can be easily separated, and the amount of time required for the separation. Both packed and capillary columns are used in gas chromatography. 

Another important characteristic of a gas chromatographic column is the thickness of the stationary phase. As shown in equation 12.25, separation efficiency improves with thinner films. The most common film thickness is 0.25 pm. Thicker films are used for highly volatile solutes, such as gases, because they have a greater capacity for retaining such solutes. Thinner films are used when separating solutes of low volatility, such as steroids. 

In general, the longer a chromatographic column, the better will be the separation of mixture components. In modem gas chromatography, columns are usually made from quartz and tend to be very long (coiled), often 10-50 m, and narrow (0.1-1.0 mm, internal diameter) — hence their common name of capillary columns. The stationary phase is coated very thinly on the whole length of the inside wall of the capillary column. Typically, the mobile gas phase flows over the stationary phase in the column at a rate of about 1-2 ml/min. 

A sample to be examined by electrospray is passed as a solution in a solvent (made up separately or issuing from a liquid chromatographic column) through a capillary tube held at high electrical potential, so the solution emerges as a spray or mist of small droplets (i.e., it is nebulized). As the droplets evaporate, residual sample ions are extracted into a mass spectrometer for analysis. 

Mixtures of substances can be separated into their individual components by passage through special (chromatographic) columns in the gas phase or liquid phase. 

GC is a means of separating components of mixtures by passing them through a chromatographic column so that they emerge sequentially. 

With highly efficient capillary chromatographic columns, very small amounts of complex mixtures can be separated in the gas phase. Generally, the separated components cannot be positively identified by GC alone. 

Column Tubing. The chromatographic column is contained in a tubing, the composition of which may have a dramatic effect on the separation process, because the sample components may also interact with the walls of the tube. Some of the materials used for columns are... 

The preliminary precipitation of proteins from milk is realized through the addition of solutions of acetic acid (1,7 mol/1) and sodium acetate (lmol/1) at t = 40-45°C before chromatographic isolation of OxTC. The precipitated proteins are separated by filtration. OxTC is detenuined in filtrate after its isolation on chromatographic column. Contents of OxTC was determined on calibration curve which is linear within concentration range 0,01-1,0 p.g/ml. 

One of the most important properties of a chromatographic column is the separation efficiency. A measure of this parameter could be the difference of the retention volume for two different compounds. The result of a GPC analysis is usually, however, only one large peak, and a separation into consecutive molar mass species is not possible. Additionally there is no standard for higher molar masses consisting only of a species that is truly monodisperse. Therefore, the application of the equation to the chromatographic resolution of low... 

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