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c/coa·posted 25 days ago by u/joaquin_ivaturi

[Suspicious] the same signature image on COAs from three vendors

Suspicious Well Actually ×8

Trying to settle this properly because the thread from last year went in circles.

The claim: water content matters. The counter-claim: it is measurement error. Both sides have been asserting it confidently for about 4 months without either producing anything.

What would actually settle it is 25 people measuring the same thing the same way. I have started; my numbers are below. They lean one way but not strongly enough for me to declare victory.

If you have data, post the data. If you have an opinion, flair it as an opinion.

0 up / 0 down47% upvoted6 commentsid 1usika4 Jul 2026

6 comments

6 in this archive, depth 3

best — the order this archive was captured in

u/ahmed_rasmussen3 points·24 days ago

Dead space in the needle hub holds a small but non-trivial volume. On low-volume draws that can be several units.

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u/amylin_amyamylin2 points·25 days ago

chromatogram or it did not happen

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u/laila_yilmaz1 point·25 days ago

Sent one vial to Janoshik and VendorInvestigate. 95.1% and 94.2%. Cost me more than the vial did and I would do it again.

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u/tuva_aalto2 points·23 days ago

chromatogram or it did not happen

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u/coa_janitorMOD1 point·23 days ago

This is an urgent-care question wearing a forum question's clothes. Please contact a clinician rather than waiting for replies.

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[removed]1 point·23 days ago

[removed by moderator]

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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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