Thin Layers and Tubes

The two main types of apparatus—thin layer and tubes—each have their advantages. With thin layer techniques the sample is simpler to apply. This can be done at alternative places in the pH-gradient. It can also be done easily after the pH-gradient has been established. The thin layer technique also permits a large number of samples to be applied on one and the same gel layer. The apparatus and technique described by Awdeh et al. (39) are really astoundingly simple. The gel layer is formed OR a glass plate and each sample is applied on a tiny piece of filter paper. Then the plate is inverted and placed directly on top of the electrodes, which are carbon rods, one moistened with phosphoric acid and the other one with an organic base or sodium hydroxide. 

Several writers have described gel immunoelectrofocusing. Catsim-poolas (66) reported good results using agarose gels. Riley and Coleman (30) have also reported this application. 

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