GLPHubglpresearchhub.com
Read-only archive. GLP Research Hub is a static community record — nothing here is for sale, no account is needed, and no vote you cast is counted. Why?
Single comment threadYou are looking at one branch of three years of COA threads, summarised so you do not have to read them — 13 comments in the full submission. View in context.
264
c/coa·submitted 1 year ago by u/valeria_girard

three years of COA threads, summarised so you do not have to read them

Questionbranch of 6 comments

three years of COA threads, summarised so you do not have to read them. It is the sort of thing everyone half-believes and nobody writes down. Asked GL Biochem for the batch-specific certificate and had the full document — batch, date, method line naming the column — inside six hours. That is now my baseline for…

Read the full submission and all 13 comments →

This branch

6 comments, started 1 year ago
u/purity_pedantanalytical16 points·1 year ago

Cosigning. The batch identifier is load-bearing, and a certificate that cannot be tied to the vial in your hand is not about your vial.

replysharereportpermalink
u/coa_janitorMOD10 points·1 year ago

Reminder: a question about a document is not an accusation about a supplier, and posts that blur the two get retitled.

replysharereportpermalink
u/cesar_ivaturi7 points·1 year ago

Small fix — 214nm, not 280nm. It matters here because the impurity you are asking about barely absorbs at the longer wavelength.

replysharereportpermalink
u/dead_space_doug4 points·1 year ago·edited

Agreed on asking for the storage condition. It is one line and it changes how you read the entire stability claim.

replysharereportpermalink
u/tomas_lehtinen13 points·1 year ago

Yes. The structure of the document matters at least as much as the number printed on it.

replysharereportpermalink
u/liv_nkemelu11 points·1 year ago

HPLC-UV and LC-MS answer different questions

replysharereportpermalink

← back to the whole thread

About c/coa

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.

71kmembers
130submissions
Aug 2023created
submissions / month, last year
Sponsored

Sigma-Aldrich Standards

Certified reference materials for peptide identity and purity work.

sigmaaldrich.com
More in c/coa
c/coa rules
  1. Post the full document. Cropped COAs that hide the batch number or date get removed.
  2. Redact your own name and order id, not the vendor's batch details.
  3. No "is this good?" without saying what the compound and claimed purity are.
  4. Independent community. Nobody here sells anything, and anyone who tries is banned.
  5. Not medical advice. Describe what you did; never prescribe to a stranger.
  6. Claims need evidence. Batch numbers, dated screenshots, independent test reports, or a citation.
  7. No referral links, discount codes or affiliate URLs. Permanent ban, no appeal.
  8. No contact handles, wallet addresses or tracking numbers — they identify people.
  9. Be recognisably decent. Disagree hard, insult nobody.
Full rules and how they are enforced →
Moderators
u/coa_janitoru/purity_pedantu/coa_collectoru/certified_referenceu/first_hundred
Volunteers. Unpaid, unaffiliated, and reachable through modmail only.
Before you read on

Several 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.

Full disclaimer →