I’ll probably get downvoted for this.
Prices moved noticeably this month across several vendors at once, which usually means something upstream changed.
Between payment processors dropping vendors and customs getting stricter, the whole thing feels less stable than it did a year ago.
Genuinely open to being corrected on this.
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For anyone arriving from search: the compound reference page has the evidence grading, and the testing tab has the actual results. Two different things, easy to conflate.
We publish failed results the same way we publish passing ones. If a company disputes a finding, that goes on the record too.
Happy to walk through how to read one of those reports if it would help. It is less intimidating than it looks once you know which three numbers matter.
Correct, and the same applies to the quantity assay.
Mass spec gives you molecular weight, which confirms identity but says nothing about whether the sequence is correct. Two different peptides can share a mass.
Agreed.
Reversed-phase HPLC with UV detection at 214nm is the standard here because the peptide bond absorbs there. If a vendor reports purity without stating the method or wavelength, the number is not comparable to anything.
VI VialCountVic · · 19 found helpful
The methodology page covers the weighting question directly. Purity gets the largest share because it is the most reliably measurable thing they assess.