Topic summary

A checklist for reading a certificate in under two minutes

Analytics › COA interpretation certificate of analysis batch & lot numbers amino acid analysis Solved

This is a generated summary. It shows the 7 most-liked posts from a topic of 47, in their original order, with the accepted answer included where one exists. It is a reading aid and it will miss nuance — the full topic is the record.

cannula_traceTL3Regular1 Apr 2026#1

A checklist for reading a certificate in under two minutes — setting out what I have, and where I think it stops being reliable.

I would like to understand what this number means before I repeat it anywhere.

A PeptideMeter report on a semaglutide lot gives 96.8% purity. The supplier certificate for the same lot states 98.1%. Both documents name a reversed-phase method; neither states the same gradient.

My question is not "who is right". It is: given that those two figures were produced by different methods, what is the largest difference I should expect from method alone, and at what point does a gap stop being explainable that way?

60 likes 4mo

m.strand_rphTL3Pharmacist Solution11 Apr 2026#4

ppm_error, post #2: "Not less than 98 per cent" is a specification. "98.3 per cent" is a result. A certificate carrying only the first has not told you what was measured. It is worth stating the boring hypothesis before the interesting one. Go to post

A chromatogram supplied as a small image is legible for peak shape and not for baseline detail. That is enough to sanity-check an integration and not enough to reproduce it.

It is a small point and it changes the answer, which is an awkward combination.

8 likes in reply to #2 4mo

r.lundgrenTL213 Apr 2026#5

Everything in post #3 holds. The case it does not cover is the one I have.

An itemised related-substances table with retention times says considerably more about the synthesis than a single total. A total tells you how much is not the main peak and nothing about what it is.

24 likes in reply to #2 3mo

t.nardoneTL3Regular28 Apr 2026#12

What fields matter on a certificate: lot number matching the vial, test date, the analytical method stated specifically, the measured result as a number, and the acceptance limit stated separately. A certificate missing any of these is weaker.

22 likes 3mo

s.teixeiraTL28 May 2026 · edited#17

forest_plot, post #8: An itemised related-substances table with retention times says considerably more about the synthesis than a single total. A total tells you how much is not the main peak and nothing about what it is. Adding a source would improve this post and I do not have one to hand. Go to post

Confirming post #16 from a second method, which matters more than confirming it from a second person.

An itemised related-substances table with retention times says considerably more about the synthesis than a single total. A total tells you how much is not the main peak and nothing about what it is.

The strength of my opinion here exceeds the strength of my evidence.

31 likes in reply to #8 3mo

impurity_tableTL3Analytical chemist20 May 2026#24

Understood, and I withdraw the assumption I opened with.

32 likes 2mo

i.balogunTL221 May 2026#25

r.lundgren, post #5: Everything in post #3 holds. The case it does not cover is the one I have. An itemised related-substances table with retention times says considerably more about the synthesis than a single total. A total tells you how much is not the main peak and nothing about what it is. Go to post

The distinction between release testing and characterisation is one industrial documents make and retail ones usually do not. It is the difference between "we tested every lot for this" and "we established this once".

On reflection I would soften that slightly.

23 likes in reply to #5 2mo

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