[Vendor] WXT vs JEEP on the same compound, same month — both cleared 97.0%
The claim in the title is exactly the claim I am making: WXT vs JEEP on the same compound, same month — both cleared 97.0%. Nothing implied beyond it.
Pulling the figures out of the title: 97.0%. All of it is written down as it happened rather than reconstructed.
Sent one vial to Medutest and Janoshik. 99.6% and a claimed 99.0%. Cost me more than the vial and I would do it again.
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.
Ask me anything specific. Anything general I will probably get wrong.
- 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
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.
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.
Spent four months confusing area% and mass% in every post I made here. One explainer thread and it clicked permanently.
Not quite. Two labs with different gradients can resolve a close-eluting impurity differently and both be reporting honestly.
identity and quantity are two questions and most documents answer one
Agreed — the itemised related substances table is the difference between a document and a receipt.
Did you get the chromatogram or only the summary line?
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.
What does the method line actually say? Not the technique — the column and the gradient.
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.
Careful — "the metadata looks odd" is a reason to ask a question, not a conclusion. Re-issues are ordinary.
axis labels included, always
Asked QSC for the batch-specific certificate and had the full document — batch, date, method line naming the column — inside six hours. That is now my baseline for everybody.
Water content 3.8%, acetate 6.2%, purity 99%, net peptide about 90% of label weight. All four numbers honest, and I had to read it twice.
Are the related substances itemised or is it a single total?
redact your own name, never the batch details
redact your own name, never the batch details
mikkel_correia has the distinction right — one is a fraction of the detector signal, the other is a fraction of the mass.
Correction: that is net peptide content, not purity. Different number, different meaning, and the document says so if you read the row label.
I would not read a rounded figure as evasive. Plenty of documents round to one decimal as house style.
My first certificate had a compound name, a percentage and a logo. I thought that was normal. It is not, and now I know what to ask for.
My first certificate had a compound name, a percentage and a logo.
Adding the bit that always gets missed: the lot on the vial has to match the lot on the page, or none of this applies to your material.
- 1Careful — "the metadata looks odd" is a reason to ask a question, not a…9 comments in this branch · started by u/freya_baptista