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c/coa·submitted 11 months ago by u/wanjiru_varga

[Question] batch — what am I missing here

Questionbranch of 9 comments

batch — what am I missing here. If this has been answered properly somewhere, link me and I will delete. Ask what the stability statement was written against — temperature, light, and whether it was the lyophilised powder or the reconstituted solution. Those are three different claims. Related substances itemised…

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9 comments, started 11 months ago
u/anders_kuusela139 points·11 months ago

Yes — and the reason to ask for the whole page is that the interesting parts are the ones people crop out to fit a screenshot.

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u/amara_halonen38 points·11 months ago

This. Area percent answers "what fraction of what the detector saw was the peak I wanted", and people read it as "how much peptide is in the vial".

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u/hassan_chowdhury27 points·11 months ago

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.

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u/janek_ferrari15 points·11 months ago

ask for the storage condition the stability statement was written against

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u/aurel_boateng33 points·11 months ago

redact your own name, never the batch details

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u/tidy_vialdrawer_watch2812 points·11 months ago

a total of 0.4% tells you less than four named impurities adding to 0.6%

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u/elodie_yilmaz31 points·11 months ago

a certificate with no method line is decorative

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u/coa_janitorMOD53 points·11 months ago

Removed — cropped document. Post the whole page or do not post it; the fields people crop are the fields that matter.

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u/dead_space_doug90 points·11 months ago·edited

What does the method line actually say? Not the technique — the column and the gradient.

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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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