Agar Gel Electrophoresis: an Advantageous Technique for the Investigation of Certain Biological Stains

The agar gel method can be used to study direct dyes, for which paper can not be used because such dyes have a high affinity for the paper. A 1% gel made up with a buffer in the range of pH 9-4, of ionic strength 0.05, and spread on 8 × 10 cm lantern slides provides suitable conditions. Dyes to be tested are placed in 1.5 mm wells made in the agar and subjected to a current of 2.5 ma/cm width, at a potential of about 115 v. Separations, if any, occur in about 20 min. Mobility is affected by ionic strength; values above 0.05 may be less satisfactory by reducing mobility and allowing excessive diffusion of the dye. The method allows resolution of dyes whose molecular charges differ by only one unit. Photographic recording is sharp, since the gel is transparent. The method can be recommended as generally useful for studying both acid and direct dyes.