How are peptides purified?

Peptide purification generally uses a reversed-phase column (such as C8, C18, etc.), 214nm. The buffer system is usually a solvent containing TFA, pH 2.0. Buffer A contains 0.1% TFA in H2O, and Buffer B contains 1% TFA/ACN/pH2.0. Dissolve with Buffer A before purification; if the dissolution is not good, dissolve with Buffer B and then dilute with Buffer A; for highly hydrophobic peptides, sometimes a small amount of Formic Acid or acetic acid needs to be added. HPLC analysis of crude peptide products, if the peptide is not long (below 15aa), there will generally be a main peak, and the main peak is usually the full-length product; for long peptides over 20aa, if there is no main peak, HPLC needs to be used with Mass to determine the molecular weight, and then determine which peak is the peptide to be synthesized.