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c/coa·submitted 1 months ago by u/anders_kuusela

what would you tell week-1 you about batch

COAbranch of 12 comments

Right, the certificate of analysis question again, but with numbers this time. I have 4 data points over 16 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…

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12 comments, started 1 months ago
u/emeka_chowdhury80 points·1 months ago

Inter-lab variance on this kind of assay is routinely 1–2 points. Different column, different gradient, different integration.

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[removed]54 points·1 months ago

[removed by moderator]

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u/receptor_bias_rick78 points·1 months ago

PDF metadata is checkable in fifteen seconds

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u/noor_cardoso34 points·1 months ago·edited

This is the correct framing. The COA structure matters as much as the number.

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u/freya_baptista9 points·1 months ago

redact your own name, not the vendor's batch details

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u/anders_kuuselaOP0 points·1 months ago

Slight fix: the number was 99.3, not 93.7. Decimal point, but a fairly consequential one.

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u/hugo_bergstrom1 point·1 months ago

Slight fix: the number was 99.3, not 93.7.

Adding to this: water content is doing more work than the comment implies.

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u/anya_correia51 points·1 months ago·edited

Yeah, 96.8% area is not the problem, the missing impurity breakdown is the problem.

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u/honest_syringe2442 points·1 months ago

What is the method line say? Not the technique, the actual method.

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u/teodor_jansen66 points·1 months ago

Yeah, 96.8% area is not the problem, the missing impurity breakdown is the problem.

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u/wrong_network_w54 points·1 months ago

No. This is the kind of confident post that gets copied into a screenshot and repeated for years. Where is the evidence.

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u/laila_yilmaz19 points·1 months ago

Cosigning. The batch number is load-bearing information.

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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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