Acrylamide solution
Heat the 45% w/v solution to 37°C to dissolve the chemicals. Adjust the volume to 1 liter with distilled H2O. Filter the solution through a nitrocellulose filter (e.g., Nalge, 0.45-micron pore size), and store the filtered solution in dark bottles at room temperature.
An alternative, but more expensive method of preparing the acrylamide stock solution is to purchase a premixed powder of acrylamide:bis from a commercial manufacturer (e.g., Bio-Rad) and to reconstitute the mixture with H2O. Stabilized, premixed solutions of acrylamide:bis are available from National Diagnostics, Atlanta, Georgia.
Cheaper grades of acrylamide and bisacrylamide are often contaminated with metal ions. Stock solutions of acrylamide made with these grades can easily be purified by stirring overnight with approx. 0.2 volume of monobed resin (MB-1, Mallinckrodt), followed by filtration through Whatman No. 1 paper.
During storage, acrylamide and bisacrylamide are slowly converted to acrylic acid and bisacrylic acid. This deamination reaction is catalyzed by light and alkali. Check that the pH of the acrylamide solution is 7.0 or less, and store the solution in dark bottles at room temperature. Fresh solutions should be prepared every few weeks.
