u/hana_lehtinen
Contributes reviews on supplier material. Based in Aalborg.
member · joined 14 May 2025
Comments — page 4 of 4
comment on [Question] how do you actually verify HPLC in c/hplc · 552 points · 1 year ago
related substances are where the story lives, not the main peak
comment on am I the only one who found oral GLP-1 harder than the injections in c/orforglipron · 31 points · 1 year ago
What was the batch number and which service?
comment on [Discussion] we are measuring LC-MS at the wrong time and calling it noise in c/hplc · -24 points · 1 year ago
instrument quality is less important than analyst consistency
comment on help me understand gradient, I have read the wiki twice in c/hplc · 8 points · 2 years ago
This is the correct method framing. Column and gradient are load-bearing fields.
comment on tried gradient for 23 weeks. here is what happened. in c/hplc · 3 points · 2 years ago
Detection wavelength? chromatogram and that changes at different wavelengths.
comment on method development vs HPLC — genuinely asking which matters more in c/hplc · 253 points · 2 years ago
Flair changed to match the content.
Yes, exactly this, and it is the bit that took me 78 weeks to accept.
comment on [Results] 87 weeks, 36kg, and purity was the hard part in c/hplc · 7 points · 2 years ago
Gradient goblin mode: changed the solvent composition 5 times, finally got good resolution on a integration peak.
comment on [Results] 87 weeks, 36kg, and purity was the hard part in c/hplc · -31 points · 2 years ago
integration decision on a shoulder changes your number by half a point on its own
comment on [Results] 87 weeks, 36kg, and purity was the hard part in c/hplc · 25 points · 2 years ago
Gradient goblin mode: changed the solvent composition 21 times, finally got good resolution on a integration peak.
comment on 8 months in and chromatogram is still the thing I get wrong in c/hplc · 491 points · 2 years ago
two labs, two different baselines, two different purity numbers, both honest
comment on why does nobody talk about method development in c/hplc · 4 points · 2 years ago
Dead space in the needle hub holds a small but non-trivial volume. On low-volume draws that can be several units.