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 that simply does not apply outside the US.
Specifics: the route I used took 2 weeks and cost roughly what I expected. The admin was worse than the cost. The thing that would have saved me the most time was knowing which document to ask for at the start.
Happy to answer questions from anyone in the same jurisdiction.
best — the order this archive was captured in
Detection wavelength? method development and that changes at different wavelengths.
The Janoshik result being close to my own HPLC is the signal, not the absolute number. Both are right.
area% and mass% are not the same and this whole post conflates them
Detection wavelength?
Yes, exactly this, and it is the bit that took me 38 weeks to accept.
Edit to your parent would help — the concentration you quoted assumes one scenario and you have written another above it.
a round-robin on baseline integration would be genuinely useful
Detection wavelength? purity and that changes at different wavelengths.
Strongly agree. Largest single impurity tells a different story than total purity.
the gradient is doing the separation work, not the column alone
the gradient is doing the separation work, not the column alone
Yes, exactly this, and it is the bit that took me 31 weeks to accept.
The practical rule people converge on is 28 days at fridge temperature after first puncture, and that comes from the preservative, not the peptide.
Titration speed is a side-effect dial far more than an efficacy dial.
instrument quality is less important than analyst consistency
Titration speed is a side-effect dial far more than an efficacy dial.
Adding to this: method development is doing more work than the comment implies.
area% and mass% are not the same and this whole post conflates them
- 1Detection wavelength? method development and that changes at different…6 comments in this branch · started by u/dead_space_doug
- 2The practical rule people converge on is 28 days at fridge temperature after…6 comments in this branch · started by u/cagrilintide_enthusiast