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c/coa·submitted 4 months ago by u/andres_restrepo

help me understand purity, I have read the wiki twice

Questionbranch of 9 comments

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 10 months without either producing anything. What would actually settle it is 31 people…

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9 comments, started 4 months ago
u/halima_boateng108 points·4 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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[removed]81 points·4 months ago

[removed by moderator]

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u/milos_trevino19 points·4 months ago

the batch number or it did not happen

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u/milos_vanhecke6 points·4 months ago

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

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u/india_generic_g12 points·4 months ago

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

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u/andres_restrepoOP5 points·4 months ago

Slight fix: the number was 99.0, not 98.9. Decimal point, but a fairly consequential one.

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u/yara_antonsen85 points·4 months ago·edited

Water content on the document? That affects your concentration math.

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u/karma_irrelevant-26 points·4 months ago

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

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u/elodie_yilmaz29 points·4 months ago

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

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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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