Capillary electrophoretic study of the degradation pathways and kinetics of the aspartyl model tetrapeptide Gly-Phe-Asp-GlyOH in alkaline solution

► The simultaneous separation of α/β-Asp isomers as well as the d-Asp containing diastereomers of a tetrapeptide was achieved by CE. ► The validated assay was employed for the determination of the isomerization and enantiomerization kinetics fitted according to a model. ► Reversal of the sequence of the first two amino acids was identified as a minor side reaction by CE-MS.