This question is not trivial. I assume that you do not have highly purified peptides as reference compounds. Usually, amino acid analysis is performed to quantify peptides. Often companies, which perform custom peptide synthesis, also offer a quantification by routine amino acid analysis. You may also consider a simplified amino acid analysis without derivatization, only based on tyrosine or phenylalanine, if your peptides contain one of these.
This question is not trivial. I assume that you do not have highly purified peptides as reference compounds. Usually, amino acid analysis is performed to quantify peptides. Often companies, which perform custom peptide synthesis, also offer a quantification by routine amino acid analysis. You may also consider a simplified amino acid analysis without derivatization, only based on tyrosine or phenylalanine, if your peptides contain one of these.
Determining peptide concentrations accurately and quickly has proven difficult for many researchers. Most commonly used methods for peptide quantitation rely on the weight of the lyophilized powder, absorbance of ultraviolet (UV) light or amino acid analysis. https://www.emdmillipore.com/Web-PR-Site/en_CA/-/USD/ShowDocument-Pronet?id=201306.9910
According to the article, “Fast and accurate peptide quantitation using the Direct Detect® spectrometer” the Direct Detect® spectrometer provides a universal, fast and accurate peptide quantitation method that does not require sample manipulation.