HPLC vs mass spectrometry — understanding peptide testing methods

Not all testing is created equal. Here's a quick breakdown of the two main methods you'll see on COAs.

HPLC (High Performance Liquid Chromatography):

• Measures purity as a percentage (e.g., 98.5%)
• Shows a chromatogram — the main peak is your peptide, smaller peaks are impurities
• Does NOT tell you the peptide's identity — just how pure the sample is
• A 99% pure sample of the wrong peptide would still show 99% on HPLC

Mass Spectrometry (MS):

• Confirms the molecular weight (identity) of the peptide
• Tells you "this IS BPC-157" vs "this is something else"
• Doesn't measure purity as precisely as HPLC
• Often shown as a mass spectrum with the molecular ion peak

What you actually want: Both. HPLC for purity, MS for identity. A vendor providing both is showing real transparency. A vendor providing only HPLC is giving you half the picture.

Red flag: A COA with only a purity percentage and no actual chromatogram image. The raw data matters — anyone can type "99% pure" on a document.