c/coa · created 18 Aug 2023
Certificates of analysis, decoded. Post the whole document, not the headline number.
CPC semaglutide 10mg. COA says 96.8%, method line says "HPLC", batch and date both present. Nothing cropped, whole page. Everyone in here talks about 98 and 99 like…
I have typed some version of this comment about four hundred times so it is going in one place. Area% is the main peak as a fraction of total UV absorbance across all…
Short answer, for anyone who finds this from a search: no. Longer version. A COA from an actual laboratory is exported from instrument software or from a LIMS. The PDF…
Trying to work out what makes a document a result rather than a general statement about a product line. The one in front of me — FGP cagrilintide — has a compound name,…
Vendor-level purity averages over time, built from independent results rather than vendor claims. Transparent methodology, open dataset.
Browse resultsRan these on the same day, same method, same column, injections back to back. One is GL Biochem raw material, one is a reseller vial of nominally the same compound and…
Title says it — is 96.8% area% actually fine or am i being sold a rounding error — so here is the boring supporting detail that makes it worth anything. 96.8%. Those…
Following on from the area% thread, because the same confusion turns up in a second form. People read a 10mg vial at 99% purity and conclude they have 9.9mg of peptide.…
area% is not mass% and here is exactly why it matters. Two minutes of reading now saves an argument later. Related substances itemised individually is a much stronger…
which fields turn a COA from a specification into a result. Change my mind, genuinely — I have no stake in being right about this. Water content 3.8%, acetate 6.2%,…
identical chromatogram on two different compounds from the same vendor. Order-by-order, with dates, because vibes are not data. My first certificate had a compound…
water content is on the COA and everyone skips it — a position I have arrived at slowly and would like tested. Why the same vial can honestly produce three different…
Posting this because the title is the whole finding — what does "related substances 1.4%" actually mean for my vial — and a number without its method is a rumour. 1.4%.…
Posting this as a discussion rather than a claim: acetate counterion is why your 10mg vial has 8.7mg of peptide. Numbers, in the order they matter: 10mg and 8.7mg. UV…
Short public-service post: the four things a COA must have or it is decorative. Asked CPC for the batch-specific certificate and had the full document — batch, date,…
PDF producer string says the file was made in a browser. is that normal — a position I have arrived at slowly and would like tested. LC-MS gives you identity; UV purity…
Reference standards, analytical reagents and system-suitability material. If you are running your own method, start with a known.
Reference standardsvendor COA says 99.2%, my Janoshik came back 97.4%. who is wrong, and before anyone asks: same batch throughout, single submission, no cherry-picking between services.…
Posting this as a discussion rather than a claim: net peptide content vs purity — two different numbers, same vial. Why the same vial can honestly produce three…
the same signature image on COAs from three vendors. Multiple orders, one buyer, which makes this a series and not a survey. Ask what the stability statement was…
Slightly embarrassed to be asking this, but: how do i tell an HPLC-UV COA from an LC-MS one at a glance. My first certificate had a compound name, a percentage and a…
Posting this because the title is the whole finding — full document, nothing cropped, tell me what i am missing — and a number without its method is a rumour. How to…
identity and quantity are two questions and most COAs answer one. It is the sort of thing everyone half-believes and nobody writes down. Asked for the storage condition…
batch is not what most of this community thinks it is. It comes up every few weeks and the answer has not changed. The document I was worried about turned out to be a…
6th independent test on HJ — 99.1% on a claimed 99.0%, and the trend is the interesting part. One vial, one service, one member paying, which is the only kind of result…
Trying to get a straight answer on this: does water content actually matter or is it forum lore at this point. LC-MS gives you identity; UV purity gives you a relative…
the area percent question that gets asked weekly, answered properly. It is the sort of thing everyone half-believes and nobody writes down. Asked FGP for the…
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.
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