Methods / Note 02

Purity and identity: two different questions.

Understand how chromatography and mass spectrometry provide complementary evidence about peptide samples in laboratory research.

Chromatography separates sample components. In peptide analysis, HPLC with UV detection helps describe the detected components under a particular method. Mass spectrometry adds information about ions and can support characterization of the expected material and impurities.

Read the evidence together.

Ask which analytical methods were used and inspect the supporting results. A purity figure alone is not a complete structural identification. Likewise, an expected mass should be interpreted with the method and other available evidence.