Is a higher area percent proof of a correct sequence?

No. A high area percent means the detector response was concentrated in one peak under that method. The sequence is checked by comparing observed mass with the mass calculated from the stated residues.

Glossary · 2026-09-24

Scientific lead: Alice Kay, Ph.D.

Peptide area percent on a chromatogram

Area percent is how many peptide Certificates of Analysis state purity. Software integrates the chromatogram, and the named peak's area is divided by the sum of the integrated areas, then shown as a percentage. The number depends on the column, the gradient, the detector wavelength, and which peaks the analyst included. Two laboratories can report different area percents for one vial if the methods differ.

Write the percentage beside the method name, not instead of it. Then read the mass. How to read a peptide COA separates those lines. A missing impurity peak on a cropped image is not the same record as the full PDF.

Frequently asked questions

Is a higher area percent proof of a correct sequence?: No. A high area percent means the detector response was concentrated in one peak under that method. The sequence is checked by comparing observed mass with the mass calculated from the stated residues.

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