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 [Discussion] can we stop arguing about method development until somebody posts a number — 57 comments in the full submission. View in context.
1.8k
c/hplc·submitted 3 months ago by u/teodor_szabo

[Discussion] can we stop arguing about method development until somebody posts a number

Discussionbranch of 8 comments

can we stop arguing about method development until somebody posts a number. I am not trying to be the "source?" guy. I would just like a source. System suitability — repeat injections, tailing factor, plate count, RSD on area — is what tells you the instrument was fit for the measurement that day. Without it, the…

Read the full submission and all 57 comments →

This branch

8 comments, started 3 months ago
u/nnt_nate32 points·3 months ago

Chased a ghost peak for three weeks. It was the plumbing. It is always the plumbing.

replysharereportpermalink
u/salma_vasquez24 points·3 months ago

Sent the same vial to PeptideMeter and Medutest. 97.9% against a claimed 97.0%. The difference was the gradient, not the material.

replysharereportpermalink
u/anya_erdogan20 points·3 months ago

That figure cannot be quoted to two decimals off that baseline. The precision is not in the data.

replysharereportpermalink
u/ewan_tulloch13 points·3 months ago

That is area percent, not mass percent. The trace cannot give you the second one.

replysharereportpermalink
u/yara_bakken16 points·3 months ago

Push back: a longer run is not automatically better resolution. You are trading peak width for time and the ratio is what matters.

replysharereportpermalink
u/ahmed_rasmussen0 points·3 months ago

Sent the same vial to PeptideMeter and Medutest.

salma_vasquez is right — the integration choice is a decision and it should be stated alongside the result.

replysharereportpermalink
u/elodie_grimaldi1 point·3 months ago

a blank injection between samples costs four minutes and settles most arguments

replysharereportpermalink
u/reflux_report1 point·3 months ago

retention time alone is not identity

replysharereportpermalink

← back to the whole thread

About c/hplc

The analytical deep end: RP-HPLC methods, gradient design, integration decisions, LC-MS confirmation, amino-acid analysis, water content, and why two labs can report 98.1% and 96.4% on the same vial and both be right. Post the chromatogram, not the summary line.

32kmembers
130submissions
Sep 2023created
submissions / month, last year
Sponsored

Sigma-Aldrich Standards

Certified reference materials for peptide identity and purity work.

sigmaaldrich.com
More in c/hplc
c/hplc rules
  1. Chromatogram or it did not happen. Axis labels included.
  2. State the method: column, gradient, detection wavelength, injection volume.
  3. Area% is not mass%. Posts that conflate them get a correction flair, not a removal.
  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/sig_figs_samu/hplc_hobbyistu/peak_area_peteu/mass_spec_maggie
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 →