EVALUATION OF PHYTIC ACID AS A BUFFER ADDITIVE FOR THE SEPARATION OF PROTEINS IN CAPILLARY ELECTROPHORESIS

The use of phytic acid to improve protein analysis by capillary electr ophoresis (CE) is becoming more and more popular. Due to its size and number of negative charges (up to 12) it provides a high ionic strengt h combined with a low conductance resulting in an efficient decrease o f wall adsorption for proteins. Because of its twelve acidic groups, p hytic acid can be used as a buffer over a wide pH range (pH 2-11). The limited wall adsorption of proteins using phytic acid-containing buff ers is observed for buffers with a pH of 5.5 and higher. With a monopr otic buffer, most of the investigated proteins show wall adsorption at the pH values studied. In case of a phytic acid buffer, wall adsorpti on is reduced by a factor of 2-4. The use of phytic acid both as a mod ifier and as a pH buffer results in more pronounced differences betwee n the Various protein mobilities compared with the use of monoprotic b uffers. As a result this feature can be used to improve resolution in protein separations.