Filling the Column

Before a column is used for any analysis, it must be conditioned thermally by heating the column overnight at an oven temperature below the upper limit of the stationary phase with a normal flow rate of carrier gas. The column should not be connected to the detector during the conditioning process. The purpose of conditioning is the removal from the column of any remaining residual volatiles and low-boiling species present in the stationary phase which could produce an unsteady baseline at elevated column temperatures, commonly referred to as column bleed, and contaminate the detector. 

Conditioning a column also helps in redistribution of the liquid phase on the solid support. The degree of conditioning depends on the nature and amount of 

Any gas chromatographic column, new or conditioned, packed or capillary, should be purged with dry carrier gas for 15 to 30 minutes before heating to a final elevated temperature to remove the detrimental presence of air. 

A column should not be heated to an elevated temperature rapidly or ballis-tically but should be heated by slow to moderate temperature programming to the final temperature desired. 

Excessively high conditioning and operating temperatures reduce the lifetime of any gas chromatographic column, 

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As manufactured, most resias have a Gaussian-Hke distributioa of particle size. Very few are as small as 0.3 mm or as large as 1.0 mm. Most are betweea 0.5—0.8 mm. A backwash before usiag aew resia is common practice to assure uniform flow during the adsorption and regeneration steps. The backwash eliminates air pockets that may have formed while filling the column and sorts the beads such that the smaller sizes are at the top of the bed and... 

At this point, fill the column half-full with the least polar eluent you will use. If this is not given, you can surmise it from a quick check of separation of the mixture on a TLC plate. This would be the advantage of an alumina TLC plate. 

Fill the column half full with the least polar eluent that you will use. If your particular formula does not give the eluents to use (this is rare) then you will have to look up the directions on... 

Slurry the swollen, settled gel in about a half of its volume of buffer and degas under vacuum for 10 min. Connect the column outlet with tubing ending in a vessel at the level of the upper border of the column. Then mount the filling reservoir to the vertical column as shown in Fig. 3.3A. Fill the column up to one-fourth to one-third of its height with buffer and pour the gel slurry without bubbles in one portion into column and reservoir. Regulate the recommended hydrostatic pressure Ah (cf. Fig. 3.3 Table 3.2) by lowering the outlet. 

When the gel has settled, fill the column with buffer and carefully insert the upper adaptor. Move the adaptor down to the surface of the packed bed and push it further 1-3 mm into the GPC gel. Avoid air bubbles and let the outlets open to avoid compression of the gel. 

Obtain a prepacked column and clamp it to a ring stand. If you must prepare your own column of IDA-agarose, use a 1 X 6-8 cm column. Pour in about 2 mL of the IDA-agarose slurry. (Be sure the column outlet is closed.) Allow the gel to settle to a column 1-2 cm high. Protect the surface of the gel by allowing a small circle of filter paper to settle onto the top. Allow most of the solution to pass through the column, close the outlet, and add buffer A to fill the column. 

Gently stir the filtration medium (enough to fill the column plus 10%) into 2X the column volume of buffer... 

Carefully pack a clean column by first filling with a third column volume of buffer (0.2M sodium phosphate, pH 6 0, containing 0.1M sodium sulfate) Swirl the slurry to resuspend it evenly, and pour it down a glass rod onto the inside wall to fill the column Allow to settle under gravity for 0.5-1 h and to let air bubbles escape (see Note 12)... 

Top up the column periodically by siphoning off excess supernatant, stirring the top of the gel (if it has settled completely), and filling the column up to the top with resuspended slurry. 

Block nonspecific binding sites by filling the column with Tris/sahne/BSA and leaving for 30 min at room temperature... 

Chiller for Auxiliary Refrigeration. The calculated load on the auxiliary refrigeration is about 350,000 B.t.u. per hour. A 40-ton refrigeration unit was chosen for this service. Before ice is produced in the freezer, and while ice fills the column, the total refrigerating load is taken by the chiller and therefore a unit larger than 350,000 B.t.u. per hour is required. 

This method may be easily mechanized [7]. The column is mounted vertically and filled with a continuous slow stream of packing material. During filling, the column is bounced on a hard surface about 100 times per minute (the column is raised about 1 cm) and is... 

Monolith Column—Porous silica column prepared in situ to completely fill the column tube with a fully porous silica foam skelton. After the organic polymer support is heated off, the silica surface is silylated in place to product bonded-phase surface. Column is high resolution and can be used at high flow rates with relatively low back-pressure (see Chapter 16). 

Another approach is to fabricate and install a precisely defined packing structure, which is carefully placed to fill the column. An example of a structured packing is shown in Fig. 8. Both types of packing are most commonly made from stainless steel. The surface area per unit volume is a key variable. Large surface area packings have lower efficiencies, higher capacities, lower pressure drops, and lower costs than small surface area packings. 

In a different study, Chen and co-workers optimized the silicate polymerization method [131]. In their approach, the outlet frit is prepared by first filling the column with a sodium silicate solution. Then, the portion of the column at which the frit is desired is brought in contact to a heating element for a few seconds and the frit is... 

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