c/hplc · created 14 Sep 2023
Chromatograms, methods, integration. Bring the raw trace.
Yes, probably, and this thread exists so I can link it instead of retyping it. Sources of legitimate disagreement on the same physical sample, roughly in order of how…
Not naming the poster, the trace is in the thread below this one and they will know. The reported figure is 98.47%. The baseline in the attached trace drifts visibly…
Method: C18 150×4.6, 5µm. 0.1% TFA in water / acetonitrile, 20→45% over 25 min. 214nm, 20µL injection. Semaglutide, reseller vial, nothing exotic. Main peak at 11.8 min…
Two years ago I bought a decommissioned system for less than a decent bicycle. Since then I have learned more analytical chemistry than I ever wanted and spent more…
Reference standards, analytical reagents and system-suitability material. If you are running your own method, start with a known.
Reference standardsResearch peptide, not a GLP-1, from a vendor I will not name because this is a methodology question rather than a vendor post. MS confirms the expected molecular mass…
Right, the HPLC question again, but with numbers this time. I have 21 data points over 38 weeks. The pattern is consistent enough that I do not think it is chance, and…
chromatogram. That is the whole post, but I will justify it. Everything else people worry about in c/dosinglogs is downstream of it. Titration speed, muscle cramps, the…
Week 17 update. 43kg down from the start, reflux basically gone since about week 69. Things that worked: consistency, protein at breakfast, walking more than I want to.…
I have had 3 orders now and I keep a table, so here is the honest summary rather than a vibe. Material has been consistent. Communication has not. Shipping has varied…
Something I noticed reading old threads that I have not seen said out loud. The advice on HPLC in this community changed substantially around the start of last year,…
Quick one. Canada here. HPLC works very differently where I live than in the threads that dominate the front page, and I keep seeing people confidently given advice…
Something I noticed reading old threads that I have not seen said out loud. The advice on integration in this community changed substantially around the start of last…
Genuinely asking, not being difficult. Everyone in c/glp1eu repeats that gradient is important. I believe it, but I have never seen anyone show why, and when I search I…
Been lurking in c/t2dglp1 for about 18 months and finally have something worth posting. Short version: week 32, 2.5mg, and gradient is the bit I still cannot get a…
Long-ish post, sorry. tl;dr at the bottom. I have been tracking method development against eGFR for 19 weeks because I could not find anyone who had. The correlation is…
Send the vial, get the number. Third-party purity and identity testing, results published to you regardless of what they say.
Test a vialSponsoredEst. 1998. ISO 9001 and cGMP, 1,500+ staff, 200+ patents. There is a fair chance the vial you are about to send for testing started here. Batch-specific COA as standard.
glbiochem.netSomething I noticed reading old threads that I have not seen said out loud. The advice on integration in this community changed substantially around the start of last…
I have had 14 orders now and I keep a table, so here is the honest summary rather than a vibe. Material has been consistent. Communication has not. Shipping has varied…
Been lurking in c/progresspics for about 6 months and finally have something worth posting. Short version: week 50, 15mg, and integration is the bit I still cannot get…
chromatogram. That is the whole post, but I will justify it. Everything else people worry about in c/reconstitution is downstream of it. Titration speed, muscle cramps,…
chromatogram. That is the whole post, but I will justify it. Everything else people worry about in c/reconstitution is downstream of it. Titration speed, early…
Quick one. Canada here. chromatogram works very differently where I live than in the threads that dominate the front page, and I keep seeing people confidently given…
Genuinely asking, not being difficult. Everyone in c/glp1eu repeats that purity is important. I believe it, but I have never seen anyone show why, and when I search I…
Something I noticed reading old threads that I have not seen said out loud. The advice on HPLC in this community changed substantially around the start of last year,…
chromatogram. That is the whole post, but I will justify it. Everything else people worry about in c/dosinglogs is downstream of it. Titration speed, reflux, the…
Quick one. Canada here. chromatogram works very differently where I live than in the threads that dominate the front page, and I keep seeing people confidently given…
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.
Independent testing plus vendor-level trend data. Community-funded, unaffiliated.
peptidemeter.comSeveral 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.
Reference