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genuine question about area percent that I am slightly embarrassed to ask
genuine question about area percent 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…
c/coa — hot, page 2
Positions 26–50 of 130.
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posted 2 months ago by u/andres_restrepo
help me understand COA, I have read the wiki twiceSlightly embarrassed to be asking this, but: help me understand COA, I have read the wiki twice. My first certificate had a compound name, a percentage and a logo. I…
2.3k
posted 2 months ago by u/isabela_nilsen
the related substances thing finally clicked for me and I want to write it downPosting this as a discussion rather than a claim: the related substances thing finally clicked for me and I want to write it down. The document I was worried about…
621
posted 2 months ago by u/soren_zamora
help me understand water content, I have read the wiki twicehelp me understand water content, I have read the wiki twice. Searched first, found three threads that contradict each other, hence the post. Asked QSC for the…
PeptideMeter — community peptide analytics
Vendor-level purity averages over time, built from independent results rather than vendor claims. Transparent methodology, open dataset.
Browse results337
posted 2 months ago by u/first_hundred
[PSA] certificate of analysis is not what most of this community thinks it iscertificate of analysis is not what most of this community thinks it is. Two minutes of reading now saves an argument later. My first certificate had a compound name, a…
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posted 2 months ago by u/blunt_coldbox29
why does nobody talk about area percentwhy does nobody talk about area percent — that is what I am asking, and I have already read the wiki twice. Water content 3.8%, acetate 6.2%, purity 99%, net peptide…
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posted 2 months ago by u/coa_janitor
the COA thing finally clicked for me and I want to write it downthe COA thing finally clicked for me and I want to write it down. Making the case below, and I expect to lose some of it in the comments. My first certificate had a…
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posted 3 months ago by u/priya_palacios
[Lab] 18th independent test on HJ — 99.2% on a claimed 99.0%, and the trend is the interesting part18th independent test on HJ — 99.2% 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…
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posted 3 months ago by u/bastian_aalto
[Question] certificate of analysis — what am I missing hereSlightly embarrassed to be asking this, but: certificate of analysis — what am I missing here. Spent four months confusing area% and mass% in every post I made here.…
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posted 3 months ago by u/first_hundred
reading certificate of analysis threads from 2024 and half of it aged badlyreading certificate of analysis threads from 2024 and half of it aged badly, and I am aware this is a minority view on this board. UV at 214nm sees the peptide bond and…
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posted 3 months ago by u/cesar_ivaturi
do related substances actually matter or is it forum lore at this pointThe title is the whole question — do related substances actually matter or is it forum lore at this point — but here is why I am asking. The PDF creation date being…
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posted 3 months ago by u/kavya_verhoeven
[Meta] proposal — a flair for water content postsproposal — a flair for water content posts. Nothing about this affects the ranking maths, before anyone asks. Ask what the stability statement was written against —…
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posted 3 months ago by u/sofia_ferreira
[Discussion] we are measuring COA at the wrong time and calling it noisewe are measuring COA at the wrong time and calling it noise. I have gone back and forth on this for months. UV at 214nm sees the peptide bond and picks up almost…
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posted 4 months ago by u/marisol_frisk
[Discussion] can we stop arguing about COA until somebody posts a numberGenuine question, and the title is the question: can we stop arguing about COA until somebody posts a number. Spent four months confusing area% and mass% in every post…
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posted 4 months ago by u/anya_moreau
[PSA] purity is not what most of this community thinks it ispurity is not what most of this community thinks it is. Two minutes of reading now saves an argument later. My first certificate had a compound name, a percentage and a…
Sigma-Aldrich — certified reference materials
Reference standards, analytical reagents and system-suitability material. If you are running your own method, start with a known.
Reference standards522
posted 4 months ago by u/anya_correia
[Discussion] we are measuring purity at the wrong time and calling it noisewe are measuring purity at the wrong time and calling it noise. Change my mind, genuinely — I have no stake in being right about this. How to ask for a batch record…
408
posted 4 months ago by u/nadia_fonseca
reading batch threads from 2024 and half of it aged badlyreading batch threads from 2024 and half of it aged badly. Making the case below, and I expect to lose some of it in the comments. My first certificate had a compound…
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posted 5 months ago by u/soren_nkemelu
[Vendor] GGPeps vs GL Biochem on the same compound, same month — both cleared 99.0%Posting this because the title is the whole finding — GGPeps vs GL Biochem on the same compound, same month — both cleared 99.0% — and a number without its method is a…
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posted 5 months ago by u/anders_kuusela
area percent — 13 things I got wrong before I got it rightarea percent — 13 things I got wrong before I got it right — a position I have arrived at slowly and would like tested. LC-MS gives you identity; UV purity gives you a…
507
posted 5 months ago by u/laila_wojcik
related substances are the most under-discussed thing on this boardrelated substances are the most under-discussed thing on this board. Change my mind, genuinely — I have no stake in being right about this. Water content 3.8%, acetate…
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posted 5 months ago by u/certified_reference
unpopular opinion: most of what gets said here about COA is guessworkThe title is the argument: unpopular opinion: most of what gets said here about COA is guesswork. Here is the rest of it. The PDF creation date being later than the…
648
posted 6 months ago by u/nabila_espinoza
[Lab] 10th independent test on ERP — 97.2% on a claimed 97.0%, and the trend is the interesting part10th independent test on ERP — 97.2% on a claimed 97.0%, and the trend is the interesting part. That is the headline. The document, the batch and the service are below…
558
posted 6 months ago by u/blunt_coldbox29
reading water content threads from 2024 and half of it aged badlyreading water content threads from 2024 and half of it aged badly. It is the sort of thing everyone half-believes and nobody writes down. Net peptide content is the…
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posted 6 months ago by u/hassan_chowdhury
does purity actually matter or is it forum lore at this pointdoes purity actually matter or is it forum lore at this point. Searched first, found three threads that contradict each other, hence the post. Asked QST for the…
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posted 6 months ago by u/dario_vermeulen
COA — 5 things I got wrong before I got it rightCOA — 5 things I got wrong before I got it right — a position I have arrived at slowly and would like tested. LC-MS gives you identity; UV purity gives you a relative…