RESUMO
Isoelectric focusing and chromatofocusing are techniques to separate amphoteric compounds based on their isoelectric points. The commonest used c ompounds to generate a pH gradient in these techniques are ampholytes. The prohibitively expensive cost of carrier ampholytes limits the application of these techniques in less advantaged parts of the world. A simple and inexpensive method is de scribed in this paper to prepare a broad pH range (pH 3 to 11) ampholytes for use in isoelectric focusing or chromatofocusingin any routine laboratory. The method involves crosslinking polyethylene polyamine to create complex cross-linked polyaminesin the first step. Whereas, the second step involves reacting the cross-linked polyamines with an unsaturated carboxylic acid to produce ampholytes.