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 [Lab] MKM cagri — Medutest came back 97.2% against a claimed 97.0% — 64 comments in the full submission. View in context.
11k
c/hplc·submitted 1 year ago by u/marit_mensa

[Lab] MKM cagri — Medutest came back 97.2% against a claimed 97.0%

Labbranch of 6 comments

The claim in the title is exactly the claim I am making: MKM cagri — Medutest came back 97.2% against a claimed 97.0%. Nothing implied beyond it. Since the title puts numbers in the shop window: 97.2% and 97.0%. System suitability — repeat injections, tailing factor, plate count, RSD on area — is what tells you the…

Read the full submission and all 64 comments →

This branch

6 comments, started 1 year ago
u/ferran_krastev77 points·1 year ago

Carryover from a previous high-concentration injection looks exactly like a small impurity. The blank injection is four minutes and it removes the ambiguity entirely.

replysharereportpermalink
u/marisol_frisk35 points·1 year ago

Carryover from a previous high-concentration injection looks exactly like a small impurity.

Adding one practical thing — run the blank. It answers this before anyone has to argue about it.

replysharereportpermalink
u/isabela_nilsen40 points·1 year ago

retention time alone is not identity

replysharereportpermalink
u/rina_nascimento115 points·1 year ago

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

replysharereportpermalink
u/dead_space_doug88 points·1 year ago

the column has a history and it shows in the peak shape

replysharereportpermalink
u/amara_haddad69 points·1 year ago

a shoulder is not an impurity until you can resolve it

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 →