u/rania_okonkwo
Contributes reviews on supplier material. Based in Seville.
member · joined 14 May 2025
Overview — page 2 of 2
comment on [Vendor] SSA vs TFC on the same compound, same month — both cleared 97.5% in c/coa · 200 points · 2 years ago
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.
comment on how much of what we believe about COA actually comes from area percent threads in c/coa · 84 points · 2 years ago
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.
comment on personal import — 12 things I got wrong before I got it right in c/customs · 76 points · 2 years ago
Not convinced. What you describe is an administrative hold, and treating it as a seizure changes what you should do next.
comment on [Discussion] the related substances advice in here is 3 years out of date in c/coa · 225 points · 2 years ago
the lot on the vial has to match the lot on the page
comment on [Lab] 18th independent test on SWB — 99.4% on a claimed 99.0%, and the trend is the interesting part in c/hplc · 362 points · 2 years ago
I would not blame the sample yet. Everything you have described is consistent with the column rather than the vial.
comment on [Lab] 18th independent test on SWB — 99.4% on a claimed 99.0%, and the trend is the interesting part in c/hplc · 500 points · 2 years ago
Bought a second-hand instrument and learned more in six months of fixing it than in three years of reading traces.
comment on [Meta] the method development rule is doing its job and people should stop complaining in c/hplc · 212 points · 2 years ago
Correcting myself upthread: I said the gradient was linear and looking again it has a hold in the middle.
comment on [Meta] the method development rule is doing its job and people should stop complaining in c/hplc · 686 points · 2 years ago
Chased a ghost peak for three weeks. It was the plumbing. It is always the plumbing.
comment on purity — 19 things I got wrong before I got it right in c/hplc · 45 points · 2 years ago
retention time alone is not identity