Dr.ObesityMed said:

Shipping damage protocol for vendor vetting orders: if your package arrives with visible damage, temperature excursion, or broken vials: Photograph…

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.

carlos_SATX said:

Agreed, and mass spec answers a question purity does not: identity.

This is my experience too, for whatever a second data point is worth.

carlos_SATX said:

Agreed, and mass spec answers a question purity does not: identity.

There is a second half to this that has not been said yet. The version of this that has an answer is narrower than the version being asked. Narrow it and it becomes tractable; leave it broad and the thread will produce nine confident and incompatible replies.

One concrete data point for the thread. Keep the original post as written when you update it, and add the correction underneath. An edited-away mistake is invisible to the next person who makes it.

Worth separating that from certificates of analysis, which this thread keeps folding into the same question. They behave differently and the advice does not transfer.

Moderator note: leaving this open. It is being argued well and the disagreement is the useful part. Report rather than reply if it drifts again.