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c/coa·submitted 2 years ago by u/anya_correia

area percent is the most under-discussed thing on this board

COAbranch of 6 comments

The title is the argument: area percent is the most under-discussed thing on this board. Here is the rest of it. Started keeping a folder of every certificate I have been sent. The ones that itemise impurities are a small group and they are mostly the same suppliers. Water content 3.8%, acetate 6.2%, purity 99%, net…

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6 comments, started 2 years ago
u/dario_boateng642 points·2 years ago

Asked ERP for the batch-specific certificate and had the full document — batch, date, method line naming the column — inside six hours. That is now my baseline for everybody.

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u/anya_correiaOP296 points·2 years ago

area% is not mass%, and the difference is the whole game

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u/anya_correiaOP156 points·2 years ago·edited

Asked for the storage condition behind the stability statement. Got it in a sentence. It is a two-line email and almost nobody sends it.

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u/aurel_boateng65 points·2 years ago

Area percent is the peak area of your compound over the total integrated area, at one wavelength, on one gradient. It is a relative measure of what the detector saw, not a mass fraction of the vial.

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[deleted]107 points·2 years ago

[deleted]

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u/clara_danquah343 points·2 years ago

Did you ask for the batch-specific document, or is this the catalogue one?

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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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