State-of-the-art and trends for the SI traceable value assignment of the purity of peptides using the model compound angiotensin I

The prohormone angiotensin I is a hypertension biomarker and was selected as a model peptide. The full mass balance approach, the peptide impurity corrected amino acid analysis, elemental analysis and quantitative nuclear magnetic resonance approaches have been investigated and optimized to compare the performance of these different methodologies for the purity mass fraction value assignment of an ANG I calibrator material.