Breakthrough during reversed phase purification often occurs for only a couple of reasons: 1) the dissolution solvent is too strong and prevents the compound from fully interacting with the stationary phase or 2) too much sample has been loaded onto the column. Peptides, particularly when part of a crude sample mixture, are known for their minimal solubility in aqueous conditions which further complicates purification efforts and often compromises recovery of purified material.  This problem is further is exacerbated when the peptide of interest is small and contains polar amino acid(s), which often results in poor retention by the C18 stationary phase commonly used in peptide purification.

In today's discussion, I'll highlight an unusual strategy to address both solubility and retention, while decreasing the breakthrough that can occur during purification of these types of peptides.