Glass-bead column method

Two different methods are in general use the glass bead column method of Rabinowitz (1964, 1973) and the density gradient centrifugation method of Boyum (1968). 

A sterile glass condenser or water jacketed column (40 X 2 cm) is clamped in a vertical position and water at 37°C is circulated around it. This size of column is large enough to fractionate leukocytes from 200 ml of blood. 

Glass beads (Type 070-5005 superbrite brand from 3 M Company, St. Paul, Minnesota) are soaked overnight in concentrated HN03 and then rinsed exhaustively in tap and distilled water before 

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Fig. 6.1. DNA synthesis in PHA-stimulated horse lymphocytes. Aliquots of 3x10 horse lymphocytes purified by the glass bead column method were incubated for various lengths of time with PHA-M in tubes in 3 ml Eagle s MEM (supplemented with 10 fig serine/ml and 7.5 fig glycine/ml and 10% autologous horse plasma). Before harvesting the cells were labelled for 6 h with [14C]thymidine (3.66 Ci/mol 1 fiCi/ml). o, Amethopterin (10 6M) was added 16 h before harvesting. , no amethopterin added. (Courtesy of Dr. B.S. Zain, 1971.)...

Benzene Glass bead column 5 ml nitrating acid 0.25 3-5 + 95 Butanone method Other aromatic... 

Zsolnay and Kiel [26] have used flow calorimetry to determine total hydrocarbons in seawater. In this method the seawater (1 litre) was extracted with trichlorotrifluoroethane (10 ml) and the extract was concentrated, first in a vacuum desiccator, then with a stream of nitrogen to 10 pi A 50 pi portion of this solution was injected into a stainless steel column (5 cm x 1.8 mm) packed with silica gel (0.063-0.2 mm) deactivated with 10% of water. Elution was effected, under pressure of helium, with trichlorotrifluoroethane at 5.2 ml per hour and the eluate passed through the calorimeter. In this the solution flowed over a reference thermistor and thence over a detector thermistor. The latter was embedded in porous glass beads on which the solutes were adsorbed with evolution of heat. The difference in temperature between the two thermistors was recorded. The area of the desorption peak was proportional to the amount of solute present. 

The process called fractional distillation uses a method of continuous redistillarion to separate mixtures of liquids the mixture is heated and the rising vapor passes up through a tall column packed with material having a high surface area, such as glass beads (Fig. 8.42). The vapor begins to condense on the beads near the bottom of the column. 

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