Electrofocusing in natural pH gradients formed by buffers: Gradient modification

Natural pH gradients formed in buffers (1) can be shifted in slope or in parallel along the pH scale by addition or substitution of buffers to obtain, for each particular fractionation problem, a gradient in which the species of interest occupies the center position. Similar to the natural pH gradients formed in Ampholine (2), the gradients formed in buffer decay concomitantly with a cathodic drift and progressive acidification of the pH gradient from the anodic end (3). Reproducibility of the pH gradient in buffer electrofocusing was found to be adequate. The stability of pH gradients with time is not affected by addition of 10 amine (basic) buffers to the standard mixture of 10 amphoteric buffers.