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 related substances — 9 things I got wrong before I got it right — 64 comments in the full submission. View in context.
1.8k
c/coa·submitted 1 year ago by u/anya_correia

related substances — 9 things I got wrong before I got it right

Labbranch of 8 comments

The title is the argument: related substances — 9 things I got wrong before I got it right. Here is the rest of it. The PDF creation date being later than the analysis date is usually a re-issue or a re-export. It is worth one question and it is not evidence of anything on its own. Ask what the stability statement…

Read the full submission and all 64 comments →

This branch

8 comments, started 1 year ago
u/tomas_lehtinen0 points·1 year ago

Related substances itemised individually is a much stronger document than a single total, because it tells you the shape of the impurity profile rather than its size.

replysharereportpermalink
u/vito_chowdhury1 point·1 year ago

Same view. SSA prints the column and the gradient, which means somebody could actually reproduce the run.

replysharereportpermalink
u/milos_trevino1 point·1 year ago

chromatogram or it did not happen

replysharereportpermalink
u/sofia_ferreira1 point·1 year ago

post the whole document, not the headline number

replysharereportpermalink
u/santiago_szabo1 point·1 year ago

Pushing back a little: a missing field is usually presentation, not concealment. Ask for the full document before drawing conclusions.

replysharereportpermalink
u/amira_dumitru1 point·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.

replysharereportpermalink
u/low_appetite_lisa1 point·1 year ago

That is not what the method line says. It names the technique; it does not certify the operator.

replysharereportpermalink
u/milos_trevino1 point·1 year ago

the lot on the vial has to match the lot on the page

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

Janoshik Analytical

Independent HPLC and mass spec. The number you get is the number they found.

janoshik.com
Sponsored

GL Biochem (Shanghai)

Custom peptides and amino acids direct from the manufacturer since 1998. ISO 9001 / cGMP. Batch COA every order.

glbiochem.net
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.
Moderators
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.