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purity is the most under-discussed thing on this board
purity is the most under-discussed thing on this board. Not a hot take, just something I have not seen said plainly here. Net peptide content is the fraction of the…
u/coa_collector
I have 1,100 COAs in a folder structure that would frighten you. Ask before you order.
long-standing contributor · archivist · joined 12 Sep 2023
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Overview — page 2 of 2
comment on [Lab] 7th independent test on WXT — 99.2% on a claimed 98.5%, and the trend is the interesting part in c/coa · 568 points · 11 months ago
Left up and flaired Explainer. This is the answer we keep linking, written properly.
comment on someone explain COA to me like I have not read a paper in years in c/coa · 55 points · 1 year ago
area% is not mass%, and the difference is the whole game
comment on purity — 6 things I got wrong before I got it right in c/coa · 72 points · 1 year ago
a certificate with no method line is decorative
comment on purity — 6 things I got wrong before I got it right in c/coa · 569 points · 1 year ago
Your name and address edited out of the screenshot above. The batch details are untouched and should stay.
comment on [Vendor] HJ vs QYB on the same compound, same month — both cleared 97.0% in c/coa · 102 points · 1 year ago
redact your own name, never the batch details
comment on [Discussion] batch is doing more work than we give it credit for in c/coa · 209 points · 1 year ago
Your name and address edited out of the screenshot above. The batch details are untouched and should stay.
comment on the batch question that gets asked weekly, answered properly in c/coa · 36 points · 1 year ago
Right, and net peptide content is where the counterion and the water go. Both numbers can be honest and very different.
comment on three years of COA threads, summarised so you do not have to read them in c/coa · 18 points · 1 year ago
net peptide content and purity are two different numbers on the same vial
comment on the data logger question that gets asked weekly, answered properly in c/coldchain · 171 points · 1 year ago
Push back: you cannot infer degradation from a temperature excursion alone. That is what testing is for.
comment on the data logger question that gets asked weekly, answered properly in c/coldchain · 196 points · 1 year ago
Moved everything off the fridge door after reading a thread here and my temperature log immediately got boring.
comment on the water content question that gets asked weekly, answered properly in c/coa · 1 points · 1 year ago
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.
comment on how much of what we believe about batch actually comes from purity threads in c/coa · 482 points · 1 year ago
axis labels included, always
comment on [Meta] the area percent rule is doing its job and people should stop complaining in c/coa · 141 points · 1 year ago
Left up and flaired Explainer. This is the answer we keep linking, written properly.
comment on [Lab] split one vial across VendorInvestigate and PeptideMeter — 97.2% and 98.4% in c/coa · 132 points · 1 year ago
Flairing this Explainer.
Adding the bit that always gets missed: the lot on the vial has to match the lot on the page, or none of this applies to your material.
comment on purity is the most under-discussed thing on this board in c/coa · 196 points · 2 years ago
redact your own name, never the batch details
comment on purity is the most under-discussed thing on this board in c/coa · 675 points · 2 years ago
post the whole document, not the headline number
comment on purity is the most under-discussed thing on this board in c/coa · 122 points · 2 years ago
Correction: that is net peptide content, not purity. Different number, different meaning, and the document says so if you read the row label.
comment on purity is the most under-discussed thing on this board in c/coa · 761 points · 2 years ago
Does the lot on the vial match the lot on the page?
comment on [Discussion] the excursion advice in here is 3 years out of date in c/coldchain · 1 points · 2 years ago
A stability statement is only meaningful with its conditions attached: temperature, duration, light exposure, and whether it covers powder or solution. Ask which.
comment on [Meta] the purity rule is doing its job and people should stop complaining in c/coa · 109 points · 2 years ago
Reminder: a question about a document is not an accusation about a supplier, and posts that blur the two get retitled.
comment on [Discussion] the related substances advice in here is 3 years out of date in c/coa · 157 points · 2 years ago
Yes. The structure of the document matters at least as much as the number printed on it.
comment on someone explain ice pack to me like I have not read a paper in years in c/coldchain · 107 points · 2 years ago
On loggers, since I was sceptical and then bought one.
A small transit logger costs a fraction of a vial and records the whole journey rather than the moment of arrival. What I learned from three of them: my lane is far more stable than I assumed, the one excursion I did capture was on a weekend, and the arrival-temperature guessing I had been doing was worthless.
If you are going to argue about cold chain, argue from a chart. It is a one-off purchase and it ends the speculation permanently.