i keep every certificate in a dated folder and compare them. two suppliers had not changed their template since 2019
lot bought purity assay/label
A-2418 2025-03 99.1% 9.6 / 10mg
A-2601 2025-08 98.7% 9.8 / 10mg
B-0114 2026-01 99.3% 9.4 / 10mg
B-0329 2026-04 98.9% 9.9 / 10mgresidual solvents matter more than people think for anything that went through a lot of purification steps
the honest summary is that a certificate tells you what the supplier says about a lot they chose to test
quick one whats the minimum a certificate has to have before you take it seriously
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not, ymmv
sorry to jump in the font on this one changes halfway down, am i being paranoid
net not gross
net peptide is gross mass minus water minus counterion. that is why 11.4mg of powder can be a correct 10mg vial
peak RRT area% note
1 0.42 0.31 solvent front
2 0.88 0.44 related substance
3 1.00 98.72 main
4 1.14 0.53 related substancewhile im here the three way match is vial, certificate, invoice. if all three agree you have something
if you only read one line on a certificate, read the lot number. if you read two, read the assay
follow up i asked WWB for the method and they sent it. that alone put them ahead of most, someone check my working
my 10mg vial weighed more than 5mg of powder, is the certificate lying
same chromatogram
why would a vial be 99 pure and still assay under label
tfa counterion runs higher by mass than acetate. if the certificate does not say, you cannot do the mass balance
nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
coming back to this no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration
thats the counterion
*VendorInvestigate not the other one
tfa or acetate, how do i tell from the paperwork
the paperwork can be perfect and the vial can still be light. weigh it, for what its worth
sorry to jump in should a certificate say which instrument and method they used
[edited]no lot no certificate
is there a standard layout or does every lab do their own
looks re-dated
mixed fonts and inconsistent kerning in one document is worth a second look
a vial can be 99.4% pure and hold 8.1mg of a 10mg label. both numbers are true and only one of them is the one you care about
gross mass on a jewellery scale plus the water content is enough to catch most underfills
purity is not assay