Positions 51–75 of 130.
three years of related substances threads, summarised so you do not have to read them, and I am aware this is a minority view on this board. UV at 214nm sees the…
The title is the argument: reading related substances threads from 2024 and half of it aged badly. Here is the rest of it. Started keeping a folder of every certificate…
how much of what we believe about related substances actually comes from certificate of analysis threads. Searched first, found three threads that contradict each…
Question in the title, detail here: can we stop arguing about related substances until somebody posts a number. Started keeping a folder of every certificate I have…
Send the vial, get the number. Third-party purity and identity testing, results published to you regardless of what they say.
Test a vialSponsoredEst. 1998. ISO 9001 and cGMP, 1,500+ staff, 200+ patents. There is a fair chance the vial you are about to send for testing started here. Batch-specific COA as standard.
glbiochem.netgenuine question about COA that I am slightly embarrassed to ask. I am not trying to be the "source?" guy. I would just like a source. The four things a certificate…
Posting this because the title is the whole finding — KP vs BCH on the same compound, same month — both cleared 97.5% — and a number without its method is a rumour.…
Something I keep coming back to: area percent is doing more work than we give it credit for. Spent four months confusing area% and mass% in every post I made here. One…
12th independent test on QST — 98.6% on a claimed 98.5%, and the trend is the interesting part. One vial, one service, one member paying, which is the only kind of…
The title is the argument: certificate of analysis — 18 things I got wrong before I got it right. Here is the rest of it. Area percent is the peak area of your compound…
Housekeeping: proposal — a flair for related substances posts. Water content 3.8%, acetate 6.2%, purity 99%, net peptide about 90% of label weight. All four numbers…
Something I keep coming back to: the certificate of analysis advice in here is 3 years out of date. Since the title puts numbers in the shop window: 3 years. How to ask…
split one vial across Janoshik and Medutest — 95.1% and 97.6%. I will put the method line and the batch identifier up front because that is what makes this checkable.…
Trying to get a straight answer on this: can we stop arguing about water content until somebody posts a number. The document I was worried about turned out to be a…
related substances — what am I missing here — that is what I am asking, and I have already read the wiki twice. Ask what the stability statement was written against —…
Slightly embarrassed to be asking this, but: why does nobody talk about batch. Spent four months confusing area% and mass% in every post I made here. One explainer…
Vendor-level purity averages over time, built from independent results rather than vendor claims. Transparent methodology, open dataset.
Browse resultsPosting this as a discussion rather than a claim: unpopular opinion: most of what gets said here about purity is guesswork. LC-MS gives you identity; UV purity gives…
batch — what am I missing here. If this has been answered properly somewhere, link me and I will delete. Ask what the stability statement was written against —…
7th independent test on WXT — 99.2% on a claimed 98.5%, and the trend is the interesting part. That is the headline. The document, the batch and the service are below…
Thinking out loud about this: purity — 9 things I got wrong before I got it right. How to ask for a batch record without it turning into a negotiation. One email, three…
The title is the whole question — someone explain COA to me like I have not read a paper in years — but here is why I am asking. The PDF creation date being later than…
we are measuring certificate of analysis at the wrong time and calling it noise. Change my mind, genuinely — I have no stake in being right about this. Water content…
Something I keep coming back to: purity — 6 things I got wrong before I got it right. My first certificate had a compound name, a percentage and a logo. I thought that…
Posting this because the title is the whole finding — HJ vs QYB on the same compound, same month — both cleared 97.0% — and a number without its method is a rumour.…
Genuine question, and the title is the question: how much of what we believe about purity actually comes from related substances threads. Related substances itemised…
batch is doing more work than we give it credit for. I have gone back and forth on this for months. The four things a certificate must carry, and what each one is for.…
How to read a certificate of analysis and what it does and does not tell you. Area% versus mass%, identity versus quantity, water content, related substances, acetate counterions, and the difference between a vendor-supplied COA and an independent test on the vial you actually received.
Certified reference materials for peptide identity and purity work.
sigmaaldrich.comSeveral compounds discussed on GLP Research Hub are sold for research use only and are not approved for human use anywhere. Nothing here is medical advice and none of it is written by your clinician. If a post reads like an instruction, treat it as a description of what one stranger did.
Reference