u/georgi_tamm

Do you have the mass, or only the UV trace?

The directory deliberately separates "we have nothing on this name" from "this went badly". Collapsing the two is how boards like this generate false certainty.

That is area percent, not mass percent. The trace cannot give you the second one.

Was in a group buy that went quiet for six weeks. It resolved in the end, but the structure meant I had no visibility and no recourse the whole time.

reproducibility beats resolution if you only get one of them

Adding one practical thing — run the blank. It answers this before anyone has to argue about it.

Started reporting my own integrations with the baseline choice stated. Arguments in my threads dropped by about half.

Domain age, registrar and certificate issuance date are all public and take about a minute to check.

Adding the practical version: buy small from anyone new, test it, then decide.

I would not blame the sample yet. Everything you have described is consistent with the column rather than the vial.

screenshots are not evidence, dates and documents are

ghost peak, check the plumbing first, it is always the plumbing

Sent the same vial to VendorInvestigate and PeptideMeter. 99.6% against a claimed 99.0%. The difference was the gradient, not the material.

What did system suitability look like on that sequence?

This is the whole methodological point of the board in one line.

What dates are we talking about — order, payment, last contact?

the pattern repeats because it works, not because people are stupid

Now I buy small from anyone new, test it, and only then commit. It has cost me a few small orders and saved me one large one.

Started reporting my own integrations with the baseline choice stated. Arguments in my threads dropped by about half.

System suitability — repeat injections, tailing factor, plate count, RSD on area — is what tells you the instrument was fit for the measurement that day. Without it, the purity figure is unanchored.

Disagree with naming anyone on that basis. One person’s bad month is not a pattern and the sidebar exists for this exact reason.

a domain registered last month with a decade of testimonials is the whole tell

Small fix — 214nm, not 210. It matters for the comparison you are making with the other run.

group buys concentrate risk in one person and nobody plans for that

Small fix — 214nm, not 210. It matters for the comparison you are making with the other run.

Disagreeing with this bit: that spread is ordinary inter-lab variance, not a disagreement about the material.

first_hundred is right — the integration choice is a decision and it should be stated alongside the result.

a domain registered last month with a decade of testimonials is the whole tell

Careful. What you are describing is a delayed shipment, and this board should not turn that into an accusation without more.

never accuse an individual, describe what happened to you

no names without evidence, that is the sidebar rule and it is a good one

Carryover from a previous high-concentration injection looks exactly like a small impurity. The blank injection is four minutes and it removes the ambiguity entirely.

Sent the same vial to Janoshik and VendorInvestigate. 99.4% against a claimed 98.5%. The difference was the gradient, not the material.

This. A shoulder that does not baseline-resolve is a question, not a quantity.

System suitability — repeat injections, tailing factor, plate count, RSD on area — is what tells you the instrument was fit for the measurement that day. Without it, the purity figure is unanchored.

Ask for the batch-specific certificate before payment. Any operation with a quality system behind it can produce one; the request costs you nothing and it filters hard.

screenshots are not evidence, dates and documents are

Is there any independent testing on file for this name anywhere?

Correction: that domain is one character different from the one you posted, which is rather the point of this thread.

Is this a shop, a group buy, or an individual reseller? They fail in different ways.

Agreed, and it is why MKM printing the column and gradient on the certificate is genuinely useful rather than decorative.