does purity by hplc at one wavelength miss things
i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does
#coa-reading 2024-07-13
Saturday19 messages4 participantstimes are UTC
Highlights from this day
- pinch_not_stretch — does purity by hplc at one wavelength miss things i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than… 21:30
- pinch_not_stretch — what does net peptide content mean next to gross mass 21:37
- pinch_not_stretch — purity is what fraction of the contents is the target. assay is how many mg are actually there. different questions nobody can authenticate a certificate from a scan.… 21:51
- pinch_not_stretch — slightly off topic but 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 21:59
- area_percent — i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does, take that with a pinch of salt a lab that… 22:17
what does net peptide content mean next to gross mass
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whats the minimum a certificate has to have before you take it seriously
sloppy not sinister
no lot number on this certificate, does that make it worthless
while im here sterility and endotoxin are separate tests and almost nobody runs either on research material
purity is what fraction of the contents is the target. assay is how many mg are actually there. different questions
nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
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a certificate should name the method, the instrument, the column and the operator. most name none of those
slightly off topic but 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
pinch_not_stretchwhile im here sterility and endotoxin are separate tests and almost nobody runs either…
the retention time on this one is different from the last lot, problem
is sterility tested as part of a normal purity certificate
i was wrong about this for a year: area percent under-reports nothing, it just answers a different question than assay does, take that with a pinch of salt
a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully
nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
[edited]test it yourself
same chromatogram
thats the counterion
one decimal versus two is usually just house style, not precision
ask for water content
no lot number, no certificate. a document you cannot tie to the vial in your hand is decoration