Mass spectrometry (MS) is an analytical technique that measures the molecular weight of compounds by ionizing them and measuring their mass-to-charge ratio. For research peptides, MS is the standard way to confirm a synthesized compound’s identity — does the peptide weigh what we expect it to weigh?
What MS Confirms
For a peptide of known sequence, the theoretical molecular weight can be calculated to four decimal places. MS measures the actual molecular weight of the synthesized compound. A research-grade COA shows the measured MW within ≤2 Daltons (Da) of theoretical — confirming the peptide is what the label says it is.
What MS Catches
- Wrong peptide: a major MW mismatch indicates the wrong compound was synthesized
- Deletion sequences: a missing amino acid shifts the MW by that residue’s mass
- Modification errors: incorrect glycosylation, lipidation, or other modifications change the MW
- Salt forms: a peptide as TFA salt vs. acetate salt has different MW
HPLC + MS Together
HPLC measures purity (how much of the sample is the target). MS measures identity (is the target what we think it is). A research-grade supplier publishes both on the per-lot COA — they answer different questions and you need both for full QC confidence.
Matte’s COA library includes HPLC + MS results for every lot.
Research use only. Not for human consumption. Statements not evaluated by the US FDA.