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c/coa·submitted 10 months ago by u/zeynep_zielinski

[Lab] split one vial across Janoshik and Medutest — 95.1% and 97.6%

Labbranch of 6 comments

split one vial across Janoshik and Medutest — 95.1% and 97.6%. I will put the method line and the batch identifier up front because that is what makes this checkable. 95.1% and 97.6%. Those are measured, not estimated, and not rounded up in my favour. The PDF creation date being later than the analysis date is…

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6 comments, started 10 months ago
u/kavya_verhoeven90 points·10 months ago

LC-MS gives you identity; UV purity gives you a relative quantity. A document with the first and not the second, or the reverse, is answering half the question.

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u/hugo_bergstrom105 points·10 months ago

Net peptide content is the fraction of the powder that is actually peptide once counterion, water and residual solvent are accounted for. A 99% pure acetate salt can still be about 85% peptide by mass.

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u/emeka_beaulieu-25 points·10 months ago

Cosigning. The batch identifier is load-bearing, and a certificate that cannot be tied to the vial in your hand is not about your vial.

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u/zeynep_zielinskiOP0 points·10 months ago

Are the related substances itemised or is it a single total?

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u/blunt_coldbox291 point·10 months ago

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

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u/foam_head_fred1 point·10 months ago

Batch number and date of analysis, are both on there?

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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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