Capillary electrophoretic separations of biotechnology‐derived proteins in E. coli fermentation broth

A capillary electrophoresis (CE) method was developed for the analysis of a recombinant DNA protein in a fermentation broth matrix. A polyacrylamidecoated capillary was employed to eliminate electroosmotic flow, facilitating relatively rapid run times. Selectivity and efficiency were enhanced significantly through the incorporation of magnesium sulfate and acetonitrile, an organic modifier, into the separation buffer. Both of these additives appeared to influence the separation by diminishing the interaction of the protein analyte with the charged micelles present in the buffer. The quantitation capabilities of the CE method were validated and found to be comparable to the standards set by chromatographic techniques previously developed for similar applications.