Influence of pH on Peptide Separations by Capillary Electrophoresis
XU Yi-Sheng1,2, LING Hao2, YANG Jin-Feng1, YU Feng1
1. School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China;
2. School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
Abstract We designed an undergraduate instrumental experiment to study the effects of pH on peptide separation by capillary zone electrophoresis (CZE). Five peptides, Bradykinin,[Hyp3]-bradykinin, Angiotensin I, Leucine Enkephalin and[Met5]-Enkaphalin, were analyzed. Both electroosmotic flow (EOF) and analyte adsorption which strongly depend on the pH, the most important issues in bioanalytical CE, were evaluated. Peptide adsorption is not observed at pH 10 for acidic peptides but weak adsorption is observed for basic peptides. Basic peptides show strongest adsorption leading to poor separation at intermediate pH 6. At pH 2.3 peptides are well resolved and show no adsorption due to their positive charge state. However, the EOF disappears at pH 2.3. This experiment is beneficial to the students who already have a basic knowledge background in analytical chemistry. It helps the chemistry students to understand the effects of environmental factors in instrumental separation analysis.
XU Yi-Sheng, LING Hao, YANG Jin-Feng, YU Feng. Influence of pH on Peptide Separations by Capillary Electrophoresis[J]. Chinese Journal of Chemical Education, 2018, 39(10): 29-32.
