[Vendor] JEEP vs WXT on the same compound, same month — both cleared 98.5%
Posting this because the title is the whole finding — JEEP vs WXT on the same compound, same month — both cleared 98.5% — and a number without its method is a rumour.
The relevant figures are 98.5%, and they come from the same log I have kept the whole time.
Area percent is the peak area of your compound over the total integrated area, at one wavelength, on one gradient. It is a relative measure of what the detector saw, not a mass fraction of the vial.
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.
I will update this if the picture changes rather than quietly leaving it up.
- JEJEEP source pageGuangzhou JEEP Biotechnology Co., Ltd. · Guangzhou · 97% here, rank 3 · shop at jeepbio.com →
- WXWXT source pageWuXi TIDES (WuXi AppTec Testing Division) · Wuxi · 92% here, rank 14 · shop at wuxitides.net →
nofollow and sponsored; nobody here is paid for it.best — the order this archive was captured in
Related substances itemised individually is a much stronger document than a single total, because it tells you the shape of the impurity profile rather than its size.
Are the related substances itemised or is it a single total?
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.
Is water content on the document? It changes your concentration arithmetic.
Small fix — 214nm, not 280nm. It matters here because the impurity you are asking about barely absorbs at the longer wavelength.
Correction: that is net peptide content, not purity. Different number, different meaning, and the document says so if you read the row label.
Did you get the chromatogram or only the summary line?
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.
UV at 214nm sees the peptide bond and picks up almost everything; at 280nm you are looking at aromatics only. Which wavelength the number came from is part of the number.
Disagree that a lower number is automatically worse. A conservative claim that survives testing is worth more than an optimistic one that does not.
The PDF creation date being later than the analysis date is usually a re-issue or a re-export. It is worth one question and it is not evidence of anything on its own.
The PDF creation date being later than the analysis date is usually a re-issue or a re-export.
This is the sentence to take away. The rest of the thread is footnotes to it.