Interplay between Peptide Length, Ionic Strength and pH in Electrophoretic Separations of Polyglutamate

Capillary electrophoresis (CE) techniques have been fundamental in advancing technology for the separation and identification of peptide and protein mixtures [1,2]. Today, they have become a staple in conjunction with mass spectrometry systems to resolve, identify and analyze protein and peptide characteristics with sensitivity and accuracy. Recent advances have miniaturized traditional CE instrumentation into microfluidic systems that can provide fast, highresolution separations with low sample volumes and better flow control [3]. However, the performance of traditional CE and microfluidic CE has rarely been compared. Furthermore, CE techniques such as on-chip gel electrophoresis, isotachophoresis [4], capillary isoelectric focusing [5] and capillary zone electrophoresis (CZE) have been applied from simple biomolecule separations to confirmatory diagnostics [6] and yet, rarely used for studying fundamental properties of peptides and proteins. In this way, CE has been underutilized as a stand-alone technique to probe structural and functional attributes of peptides.