USE OF ZWITTERIONIC DETERGENTS FOR THE SEPARATION OF CLOSELY-RELATED PEPTIDES BY CAPILLARY ELECTROPHORESIS

Capillary electrophoresis incorporating hydrophobic selectivity is sho wn to be a powerful technique for separating closely related peptide s pecies. In this work, hydrophobic interaction was induced through the addition of suitable amounts of a zwitterionic detergent dodecyl-N,N-d imethyl-3-ammonio-1-propanesulfonate) and further modified with organi c solvents. A neutral, hydrophilic-coated capillary was used to minimi ze electroosmotic flow. Two test solutes, Met(15)- and Leu(15)-gastrin , were employed to probe hydrophobic selectivity with various electrop horetic conditions. The nature and concentration of the detergent and the organic modifier were varied to adjust the selectivity. Operation near the critical micelle concentration of the zwitterionic detergent in the presence of acetonitrile or various alcohols produced the highe st hydrophobic selectivity among the conditions studied. The zwitterio nic detergent approach was also briefly compared to the use of non-ion ic detergents for hydrophobic selectivity.