Home › Guides › HPLC vs Mass Spec: What Each Peptide Test Actually Tells You By TorontoHealth Editorial · Updated June 17, 2026
HPLC vs Mass Spec: What Each Peptide Test Actually Tells You
The core idea: HPLC and mass spectrometry answer different questions. Mass spec confirms identity — is this the molecule it claims to be? HPLC measures purity — how much of the sample is that molecule versus everything else? A complete COA needs both.
What mass spec proves
Mass spectrometry weighs the molecule and matches it to the expected mass. It answers "is this the right compound?" — but on its own it says little about how much filler or by-product rides along.
What HPLC proves
HPLC separates a sample into its components and reports the percentage that is the target compound. It answers "how clean is it?" — but on its own it doesn't confirm the main peak is the right molecule.
Why one alone isn't enough
A high HPLC purity number on the wrong molecule is meaningless, and a confirmed identity with unknown purity is half a picture. Read both, together.