764
three years of purity threads, summarised so you do not have to read them
Right, the method development question again, but with numbers this time. I have 11 data points over 24 weeks. The pattern is consistent enough that I do not think it…
gradient
Every GLP Research Hub submission tagged to gradient, ranked by score. Discussed in 1 community.
Communities covering this
734
unpopular opinion: chromatogram is massively overrated
I have had 23 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…
722
the gradient question that gets asked weekly, answered properly
Genuinely asking, not being difficult. Everyone in c/glp1eu repeats that method development is important. I believe it, but I have never seen anyone show why, and when…
559
what would you tell week-1 you about method development
Something I noticed reading old threads that I have not seen said out loud. The advice on purity in this community changed substantially around the start of last year,…
Sigma-Aldrich — certified reference materials
Reference standards, analytical reagents and system-suitability material. If you are running your own method, start with a known.
Reference standards522
the HPLC thing finally clicked for me and I want to write it down
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…
522
[Discussion] we are measuring LC-MS at the wrong time and calling it noise
I have had 23 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…
519
[Question] what is a reasonable system suitability RSD for this work
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…
393
someone explain LC-MS to me like I have not read a paper in years
Posting this because I searched for it and got nothing useful. Setup: 0.5mg, week 62, constipation present but not ruining anything. I changed exactly one variable —…
369
integration — 21 things I got wrong before I got it right
purity. That is the whole post, but I will justify it. Everything else people worry about in c/reconstitution is downstream of it. Titration speed, reflux, the endless…
308
unpopular opinion: purity is massively overrated
Been lurking in c/progresspics for about 15 months and finally have something worth posting. Short version: week 81, 12.5mg, and gradient is the bit I still cannot get…
289
[Lab] SSA cagri — Medutest came back 97.4% against a claimed 96.2%
Trying to settle this properly because the thread from last year went in circles. The claim: integration matters. The counter-claim: it is measurement error. Both sides…
253
help me understand gradient, I have read the wiki twice
Posting this because I searched for it and got nothing useful. Setup: 2.5mg, week 89, sulphur burps present but not ruining anything. I changed exactly one variable —…
251
the LC-MS question that gets asked weekly, answered properly
Been lurking in c/t2dglp1 for about 6 months and finally have something worth posting. Short version: week 18, 2.5mg, and gradient is the bit I still cannot get a…
242
[Question] method development — what am I missing here
Been lurking in c/t2dglp1 for about 3 months and finally have something worth posting. Short version: week 4, 10mg, and HPLC is the bit I still cannot get a straight…
215
stalled for 12 weeks at 1.0mg and I refuse to panic this time
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,…
Janoshik Analytical — independent HPLC & mass spec
Send the vial, get the number. Third-party purity and identity testing, results published to you regardless of what they say.
Test a vialSponsoredGL Biochem (Shanghai) Ltd. — the synthesis house
Est. 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.net182
peak at 4.2 min, nobody can tell me what it is, ideas
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…
158
integration vs purity — genuinely asking which matters more
Long-ish post, sorry. tl;dr at the bottom. I have been tracking LC-MS against eGFR for 15 weeks because I could not find anyone who had. The correlation is weaker than…
113
[Correction] you cannot report area% to two decimals off that baseline
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.…
111
ghost peak turned out to be plumbing. always plumbing.
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…
105
bought a second-hand HPLC. worst best decision of my life. AMA
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…
84
my A1c moved and I cannot work out whether method development is why
Right, the LC-MS question again, but with numbers this time. I have 2 data points over 16 weeks. The pattern is consistent enough that I do not think it is chance, and…
0
[Method] 220nm vs 214nm and what you lose at each
Long-ish post, sorry. tl;dr at the bottom. I have been tracking purity against ApoB for 35 weeks because I could not find anyone who had. The correlation is weaker than…
0
the LC-MS thing finally clicked for me and I want to write it down
Right, the HPLC question again, but with numbers this time. I have 3 data points over 20 weeks. The pattern is consistent enough that I do not think it is chance, and…
0
three years of LC-MS threads, summarised so you do not have to read them
Posting this because I searched for it and got nothing useful. Setup: 2.5mg, week 47, injection-site soreness present but not ruining anything. I changed exactly one…
-43
help me understand chromatogram, I have read the wiki twice
I have had 12 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…