Amino Acid Analysis

Amino Acid Analysis

Quantitative analysis of peptides is complicated by the presence of water and counterions, which make the net amount of peptide ~60-80% of the measured (gross) weight of a peptide. The water and counterions (usually trifluoroacetate, acetate, or chloride) can be measured separately, but the net peptide content (NPC) can readily be measured by quantitative amino acid analysis (AAA). Stein and Moore developed AAA as analytical technique for aiding protein structure determination, and their incomparable contribution to biochemistry earned them the Nobel Prize in Chemistry in 1972. Stein and Moore’s technique is still the main method used for AAA today and involves the use of a high performance cation exchange separation followed by a post-column derivatization that allows sensitive detection of the amino acids. The average sensitivity using this technique is in the 0.5-1 nanomole range of material.

New England Peptide is a premier provider of AAA services. This gives our customers additional confirmation of amino acid integrity in the final peptide products, as well as quantitative information about the net peptide content of their product. In this way, customers can order an exact net peptide for their sensitive bioassay work. Additionally, the explosion of research in stable isotope dilution (SID)-based mass spectrometry assays for protein quantitation requires AAA to provide exact molar quantitation and/or aliquotting of peptide isotopologues. NEP's NEPTune™ line of peptide products for proteomics applications utilizes AAA to provide accurate and precise AAA measurement of peptide concentrations or amounts for "mass spectrometry assay-ready" custom products.

***NEP's amino acid analysis assay is tested daily vs NIST protein standards and maintains a  CV of <5%.***

Amino Acid Analysis costs $150 per sample for single analysis.

Contact to submit your samples for AAA today.

Our sample submission form can be downloaded here.


"Over the past 8 years we have used NEP for synthesis of many hundreds of peptides. The quality of NEP’s product is consistently very high. The company is deeply knowledgeable in all aspects of peptide synthesis, highly collaborative, and keenly interested in meeting the changing needs of their customers with respect to scale and formatting for delivery of peptides. One example is their flash-purified product which meets the need for initial draft-level evaluation without breaking the bank. Our experience with NEP’s antibody production capabilities has also been very good..."
Steven Carr, PhD - Director of Proteomics, Broad Institute