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 [Question] is 96.8% actually fine or am I being sold a rounding error — 19 comments in the full submission. View in context.
3k
c/hplc·submitted 6 months ago by u/hplc_hobbyist

[Question] is 96.8% actually fine or am I being sold a rounding error

Questionbranch of 7 comments

is 96.8% actually fine or am I being sold a rounding error, and before anyone asks: same batch throughout, single submission, no cherry-picking between services. 96.8% — those are the numbers, and they are the ones I am willing to defend. UV response is not uniform across species. At 214nm you are looking at the…

Read the full submission and all 19 comments →

This branch

7 comments, started 6 months ago
u/crosspost_bot_no236 points·6 months ago·edited

Disagree. Inter-lab spread of a point or two on this assay is ordinary and calling it a discrepancy misleads people.

replysharereportpermalink
u/hamza_weiss130 points·6 months ago

What did system suitability look like on that sequence?

replysharereportpermalink
u/ahmed_rasmussen72 points·6 months ago

What did system suitability look like on that sequence?

This is the whole methodological point of the board in one line.

replysharereportpermalink
u/nora_lundgren20 points·6 months ago

retention time alone is not identity

replysharereportpermalink
u/hplc_hobbyistruns their own column10 points·6 months ago

Right. And a blank between injections settles the carryover argument before it starts.

replysharereportpermalink
u/isabela_nilsen5 points·6 months ago

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

replysharereportpermalink
u/hplc_hobbyistOPruns their own column146 points·6 months ago

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

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

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/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.
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.