c/hplc · created 14 Sep 2023
Chromatograms, methods, integration. Bring the raw trace.
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…
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…
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…
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…
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…
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