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c/coa·posted 7 months ago by u/sofia_ferreira

anyone else notice water content kicking in around week 39

Explainer Clean Column ×3 Receipts ×2

I have had 20 orders now and I keep a table, so here is the honest summary rather than a vibe.

Material has been consistent. Communication has not. Shipping has varied by about 24 days on nominally the same lane, which matters more in summer than in February.

The independent number came back 98.4% against a claimed 98.6%, which I read as agreement rather than a discrepancy — inter-lab variance on this assay is a point or two either way and treating one lab as ground truth is how people end up in pointless arguments with vendors.

Batch number is in the comments. Ask if you want the method.

20,594 up / 18,249 down53% upvoted36 commentsid 109dnz25 Dec 2025

36 comments

23 in this archive, depth 4

best — the order this archive was captured in

u/spreadsheet_gremlindata0 points·7 months ago

Crossposting this to c/progresspics because the people who need it are not reading this community.

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u/sofia_ferreira1 point·7 months ago

What is the method line say? Not the technique, the actual method.

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u/santiago_szabo0 points·7 months ago

the method line is doing real work, not just window dressing

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u/santiago_szabo1 point·7 months ago

Small correction: the trial was 22 weeks, not 34. Does not change your point but people will quote it.

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u/liv_nkemelu108 points·7 months ago

The COA I was holding said 96.8% area and I thought it was trash. Turns out the method was solid and the impurity profile was clean.

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u/sofia_ferreiraOP69 points·7 months ago

PDF metadata is checkable in fifteen seconds

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u/sofia_ferreiraOP41 points·7 months ago

redact your own name, not the vendor's batch details

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u/anya_correia9 points·7 months ago

the batch number or it did not happen

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u/ismael_eriksen21 points·7 months ago·edited

What were the related substances listed individually?

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u/katrin_girard7 points·7 months ago·edited

the counterion is part of the mass you paid for

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u/blunt_coldbox2918 points·7 months ago

post the whole document, not the headline number

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u/katrin_girard72 points·7 months ago·edited

This is the correct framing. The COA structure matters as much as the number.

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u/hugo_bergstrom58 points·7 months ago

Tested the GLB raw material and a reseller vial side-by-side. Same purity claim, different impurity profiles. Handling matters.

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u/soren_nkemelu82 points·7 months ago·edited

Tested the GLB raw material and a reseller vial side-by-side.

Disagree on that part. 97.2% and 97.4% on the same vial is normal.

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[removed]29 points·7 months ago

[removed by moderator]

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u/santiago_szabo51 points·7 months ago·edited

The evidence standard in c/vendorvetting gets called too strict about once a month, and every time, the thread ends with the complainant agreeing.

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u/anya_correia20 points·7 months ago

the method line is doing real work, not just window dressing

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u/halima_boateng11 points·7 months ago

Slight fix: the number was 98.7, not 99.0. Decimal point, but a fairly consequential one.

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u/bastian_moreau42 points·7 months ago

Metadata check caught a COA that was created in a browser four months after the analysis date. Not evidence of fraud, but worth flagging to WWB.

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u/nadia_kjaer27 points·7 months ago

Batch number and date of analysis? Both are load-bearing.

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u/sofia_ferreiraOP0 points·7 months ago

purity and net content are two different numbers, same vial

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u/mikkel_correia1 point·7 months ago·edited

post the whole document, not the headline number

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u/zeynep_zielinski12 points·7 months ago

Did they give you the chromatogram or just the summary line?

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About c/coa

How to read a certificate of analysis and what it does and does not tell you. Area% versus mass%, identity versus quantity, water content, related substances, acetate counterions, and the difference between a vendor-supplied COA and an independent test on the vial you actually received.

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