Should two lots show the same retention time?

Only if they were run by the same stated method. Different columns or gradients move the peak. Record the method name printed on each file.

Is retention time a purity percentage?

No. Time locates the peak. Area percent describes how much of the integrated signal sits in that peak.

Glossary · 2026-09-24

Scientific lead: Alice Kay, Ph.D.

HPLC retention time, laboratory definition

Retention time is the time at which a peak appears on a chromatogram. It depends on the column, the solvent program, the flow, and the temperature of that method. A number from one HPLC file cannot be pasted onto a different method and called a match. UPLC runs are a different method again, even when the peptide name is the same.

Retention time supports a discussion of separation. It is not, by itself, an identity result. Pair it with the area percent and with the mass line when the PDF has one. The method note is how peptide purity is measured. Research-use only.

Frequently asked questions

Should two lots show the same retention time?: Only if they were run by the same stated method. Different columns or gradients move the peak. Record the method name printed on each file.
Is retention time a purity percentage?: No. Time locates the peak. Area percent describes how much of the integrated signal sits in that peak.

Research-use only. BlueNex Labs does not provide medical or veterinary advice. Confirm your institution’s policies before purchase.