[Suspicious] the same signature image on COAs from three vendors
the same signature image on COAs from three vendors. Multiple orders, one buyer, which makes this a series and not a survey. Ask what the stability statement was written against — temperature, light, and whether it was the lyophilised powder or the reconstituted solution. Those are three different claims. Related…
Net peptide content is the fraction of the powder that is actually peptide once counterion, water and residual solvent are accounted for. A 99% pure acetate salt can still be about 85% peptide by mass.
Careful — "the metadata looks odd" is a reason to ask a question, not a conclusion. Re-issues are ordinary.
net peptide content and purity are two different numbers on the same vial
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Area percent is the peak area of your compound over the total integrated area, at one wavelength, on one gradient. It is a relative measure of what the detector saw, not a mass fraction of the vial.
Correction: that is net peptide content, not purity. Different number, different meaning, and the document says so if you read the row label.