[Vendor] TFC vs SSA on the same compound, same month — both cleared 98.0%
Numbers in the title, numbers in the post. TFC vs SSA on the same compound, same month — both cleared 98.0%.
Figures up front so nobody has to dig: 98.0%.
Sent one vial to VendorInvestigate and PeptideMeter. 97.8% and a claimed 97.0%. Cost me more than the vial and I would do it again.
Started keeping a folder of every certificate I have been sent. The ones that itemise impurities are a small group and they are mostly the same suppliers.
Ask me anything specific. Anything general I will probably get wrong.
- TFTFC source pageTianjin Finder Chemical Co., Ltd. · Tianjin · 98% here, rank 1 · shop at tfcpeptides.com →
- SSSSA source pageShanghai Sigma-Audley New Material Technology Co., Ltd. · Shanghai · 90% here, rank 17 · shop at shanghaisigmaaudley.com →
nofollow and sponsored; nobody here is paid for it.best — the order this archive was captured in
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.
Right, and net peptide content is where the counterion and the water go. Both numbers can be honest and very different.
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.
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.
The document I was worried about turned out to be a re-issue with a later creation date. Asked, got the original, entirely ordinary.
Does the lot on the vial match the lot on the page?
Yes — and the reason to ask for the whole page is that the interesting parts are the ones people crop out to fit a screenshot.
That is the catalogue certificate rather than the batch-specific one. Same layout, completely different status.