Chromatography - Glossary - peptidetesting.cc

Chromatography is a laboratory separation method used to divide mixtures into components as they move through a column. In peptide testing, chromatography helps estimate purity by comparing the main target peak in a chromatogram with other detected peaks to calculate the relative amount of each substance.

Chromatography separates peptide mixtures in a column

Chromatography works by passing a liquid mobile phase through a column containing a solid stationary phase. As the peptide mixture travels through the column, its components separate because each molecule is attracted differently to the two phases. High-Performance Liquid Chromatography (HPLC) is commonly used for peptides, often separating molecules based on their water-repelling properties.

The result is a chromatogram, a graph where each separated component appears as a peak. The area under a peak corresponds to its relative amount in the mixture. When you review a lab report, chromatography supports the purity calculation by comparing the main target peak with all other detected signals. It only indirectly suggests identity by matching peak timing to a known reference standard.

Main limits when interpreting chromatography results

Chromatography is not Mass Spectrometry (MS): HPLC separates mixtures into components, while Mass Spectrometry identifies molecular structure and chemical identity.
Purity versus identity: A single peak on an HPLC report supports the relative purity of a sample but does not prove that the substance is the correct peptide.
Safety and contaminants: High purity does not guarantee safety. Standard HPLC cannot detect bacterial endotoxins, residual solvents, or heavy metals, which require separate testing methods.

Chromatography separates peptide mixtures in a column

Main limits when interpreting chromatography results

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