water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
#coa-reading 2026-06-23
Tuesday17 messages6 participantstimes are UTC
Highlights from this day
- unsolicited_dm — i asked GL Biochem for the method and they sent it. that alone put them ahead of most, i could be wrong 16:16
- unsolicited_dm — if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not 16:24
- unsolicited_dm — the certificate from HJ is the one i use to teach this because it actually has a populated impurity table 16:25
- void_volume — is sterility tested as part of a normal purity certificate 16:52
i asked GL Biochem for the method and they sent it. that alone put them ahead of most, i could be wrong
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check the lot
retention time shifts between runs are normal. relative retention time is the number to compare, i have it written down somewhere
why do some certificates report to one decimal and some to two
if the certificate date precedes the lot date, ask. sometimes it is sloppiness and sometimes it is not
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the certificate from HJ is the one i use to teach this because it actually has a populated impurity table
[edited]is water content normally on a certificate or do you have to ask
residual solvents matter more than people think for anything that went through a lot of purification steps
if you only read one line on a certificate, read the lot number. if you read two, read the assay
nobody can authenticate a certificate from a scan. you authenticate the material by testing it yourself
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how do you verify a certificate is actually from the lab it says
not detected means nothing
does anyone actually check the residual solvents section
is sterility tested as part of a normal purity certificate
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does purity by hplc at one wavelength miss things