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Single comment threadYou are looking at one branch of three years of certificate of analysis threads, summarised so you do not have to read them — 70 comments in the full submission. View in context.
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c/coa·submitted 1 year ago by u/milos_trevino

three years of certificate of analysis threads, summarised so you do not have to read them

COAbranch of 9 comments

Right, the purity question again, but with numbers this time. I have 24 data points over 10 weeks. The pattern is consistent enough that I do not think it is chance, and boring enough that nobody is going to screenshot it, which is usually a good sign. The thing I would flag for anyone new: the effect I am describing…

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9 comments, started 1 year ago
u/emil_agyeman74 points·1 year ago

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

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u/anders_kuusela35 points·1 year ago

area% is not mass%, and here is exactly why it matters

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u/liv_nkemelu24 points·1 year ago

area% is not mass%, and here is exactly why it matters

Yes, exactly this, and it is the bit that took me 53 weeks to accept.

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u/blunt_coldbox2919 points·1 year ago

purity and net content are two different numbers, same vial

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u/hugo_bergstrom0 points·1 year ago

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

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u/wrong_network_w35 points·1 year ago

area% is not mass%, and here is exactly why it matters

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u/step_therapy_s28 points·1 year ago·edited

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

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u/kavya_verhoeven35 points·1 year ago

chromatogram or it did not happen

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u/liv_nkemelu22 points·1 year ago

Not to be pedantic but certificate of analysis and COA are being used interchangeably and they are not interchangeable in real life.

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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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