traveltech_sara said:They are not contradictory, they measure different things, and this is the single most common misreading of a certificate.
Agreed, and mass spec answers a question purity does not: identity. High purity tells you one thing dominates the chromatogram, not that it is the molecule you ordered. A mass within about a dalton of expected is the identity check.
Correct me if the detail matters more than I have assumed.
SurmountFan_IN said:Right, and one flattering data point from a group buy is not consistency.
Saving this. It is the first explanation that did not require me to already understand it. Taking it to my next appointment.
traveltech_sara said:They are not contradictory, they measure different things, and this is the single most common misreading of a certificate.
I am more sceptical of certificates as a category than this thread is. The document tells you about a sample somebody chose to send, at a moment in time, and nothing about the vial in your hand. Independent purchase-and-test is a different quality of evidence and everything else is inference.
Ask again with the specifics and you will get a better answer than this one.
Sigma-Aldrich — Research-Grade Standards
Certified reference materials, analytical reagents, and research-grade standards for peptide verification. Trusted by laboratories worldwide.
Shop Reference StandardsPurityPaulOR said:Six orders from the same supplier over eight months, every one independently tested, and the consistency is the part worth reporting rather than any…
Shipping damage protocol for vendor vetting orders: if your package arrives with visible damage, temperature excursion, or broken vials:
- Photograph EVERYTHING before discarding packaging
- Note the temperature of the cold pack (liquid = possibly too warm)
- Contact the vendor within 24 hours with photos
- Request a replacement shipment or refund
- Do NOT use potentially compromised medication
Reputable vendors will replace damaged shipments without argument. If they push back, that's a red flag about the vendor.
Moderator note: reminder that nothing in this thread is medical advice, and that clinical claims need a source. Carry on.