Cosmic Peptides research library

Net peptide content

The fraction of a weighed peptide powder that is the peptide itself, the rest being counter-ions, bound water and residual solvent.

Last reviewed · Editorial policy

A lyophilised peptide is never 100% peptide by weight. Alongside the peptide it contains counter-ions (most often trifluoroacetate or acetate), water held by the solid, and traces of solvent. Net peptide content is the peptide's share of the total mass, and it is commonly well below 100%.

It is measured by amino acid analysis, by elemental (nitrogen) analysis or by other quantitative methods, and it is independent of chromatographic purity: a material can be 99% pure by HPLC yet have a net peptide content of 75%, because HPLC does not see the counter-ions or water.

When a solution of exact peptide concentration is needed, the weighed mass is corrected by the net peptide content.

See also

For in vitro laboratory research only. Not for human or veterinary use. This library describes chemistry, analytical methods and published laboratory research; it gives no guidance on use in people or animals.