Gel Preparation and Storage

Before a gel slurry is packed into the column, it should be defined and deaerated. Defining is necessary to remove very fine particles, which would reduce flow rates. To define, pour the gel slurry into a graduated cylinder and add water equivalent to two times the gel volume. Invert the cylinder several times and allow the gel to setde. After 90 to 95% of the gel has setded, decant the supernatant, add water, and repeat the settling process. Two or three defining operations are usually sufficient to remove most small particles. 

Deaerating (removing dissolved gases) should be done on the gel slurry and all eluting buffers. Gel particles that have not been deaerated tend to 

Antimicrobial agents must be added to stored, hydrated gels. One of the best agents is sodium azide (0.02°/o). 

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The mechanical properties of actin filament networks depend on the manner in which actin monomer is prepared and stored, as well as how they are polymerized conditions. Differences in mechanical properties are not the consequence of using two different types of forced oscillatory rheometers. Xu et aid found that filaments assembled in EGTA and Mg from fresh, gel-filtered ATP-actin monomer (1 mg/mL) have an elastic storage... 

Sample Preparation and Irradiation. The F-cyclobutane used in these studies was obtained from Air Products and Chemicals, Inc. and contained only small amounts of impurities it was repurified using preparative gas chromatography. The column was 2.5 meters long, 3/8 inches in diameter, packed with silica gel of 60-200 mesh (W. H. Curtin), and was connected between the storage tank of F-cyclobutane and the vacuum line. After the column was evacuated to high vacuum over several hours, the F-cyclobutane was released cautiously from the tank. At the arrival of the first traces of gas, the pressure in the vacuum line increased. The first portion of the repurified gas was discarded. The main fraction of F-cyclobutane did not contain any impurities which could be detected by gas chromatography. 

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