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c/coa·posted 3 months ago by u/priya_palacios

[Discussion] we are measuring purity at the wrong time and calling it noise

Discussion Clean Column ×9

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

The claim: certificate of analysis matters. The counter-claim: it is measurement error. Both sides have been asserting it confidently for about 15 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.

770 up / 264 down74% upvoted20 commentsid z60dt428 Apr 2026

20 comments

12 in this archive, depth 4

best — the order this archive was captured in

u/tomas_lehtinen49 points·3 months ago·edited
nope. mine was the opposite.
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u/chidi_demir26 points·3 months ago

Yeah, 96.8% area is not the problem, the missing impurity breakdown is the problem.

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u/soren_nkemelu20 points·3 months ago

Not convinced. The evidence does not support that reading.

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u/priya_palaciosOP29 points·3 months ago

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

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u/coa_collectorMOD12 points·3 months ago

Flair changed to match the content. Read the sidebar before posting next time and we are square.

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u/yannick_haddad12 points·3 months ago

Respectfully this is a sample of one presented as a finding.

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[removed]5 points·3 months ago

[removed by moderator]

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u/blunt_coldbox296 points·3 months ago

no "is this good?" without saying what the compound and claimed purity are

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u/sofia_danquah5 points·3 months ago

Strongly agree. Mass% and area% are answering different questions on the same document.

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u/milos_vanhecke3 points·3 months ago

post the whole document, not the headline number

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u/emil_agyeman1 point·3 months ago·edited

post the whole document, not the headline number

Adding to this: related substances is doing more work than the comment implies.

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u/reflux_report7 points·3 months ago·edited

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 MKM.

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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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