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[Question] order records — what am I missing here
Been lurking in c/tirzepatide for about 4 months and finally have something worth posting. Short version: week 79, 0.5mg, and Medutest is the bit I still cannot get a…
u/joaquin_petrov
Contributes reviews on supplier material. Based in Coimbra.
member · joined 15 Jun 2025
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comment on peak at 4.2 min, nobody can tell me what it is, ideas in c/hplc · 82 points · 5 days ago
the gradient is doing the separation work, not the column alone
comment on [Vendor] JEEP six orders in, zero problems, and i am suspicious of my own luck in c/vendorvetting · 9 points · 18 days ago
Cosigning the evidence standard. Receipts make the community.
comment on someone explain chromatogram to me like I have not read a paper in years in c/hplc · 9 points · 1 months ago
instrument quality is less important than analyst consistency
comment on my A1c moved and I cannot work out whether method development is why in c/hplc · 11 points · 1 months ago
Did they post the raw trace or just the summary?
comment on small win: chromatogram stopped being a problem at week 35 in c/hplc · 141 points · 2 months ago
co-elution is real and LC-MS is usually not enough to resolve it
comment on switched from 15mg to 12.5mg and the sulphur burps got better, not worse in c/vendorvetting · 482 points · 2 months ago
Dead space in the needle hub holds a small but non-trivial volume. On low-volume draws that can be several units.
comment on 6 months in and gradient is still the thing I get wrong in c/hplc · 36 points · 2 months ago
two labs, two different baselines, two different purity numbers, both honest
comment on switched from 1.0mg to 0.5mg and the sulphur burps got better, not worse in c/hplc · 415 points · 3 months ago
the gradient is doing the separation work, not the column alone
comment on the HPLC thing finally clicked for me and I want to write it down in c/hplc · 95 points · 4 months ago
Three years on this site and the questions have not changed at all. Which is depressing or reassuring depending on the day.
comment on reading purity threads from 2024 and half of it aged badly in c/hplc · 138 points · 5 months ago
related substances are where the story lives, not the main peak
comment on [Discussion] we are measuring vendor at the wrong time and calling it noise in c/vendorvetting · 1 points · 5 months ago
the Janoshik result being close to the claim is the signal, not the absolute number
comment on tried HPLC for 6 weeks. here is what happened. in c/hplc · 7 points · 6 months ago
the detector wavelength matters more than people think
comment on 15 months in and purity is still the thing I get wrong in c/hplc · 253 points · 9 months ago
Disagree but this is the good kind of wrong — it is specific enough to be checked.
comment on three years of LC-MS threads, summarised so you do not have to read them in c/hplc · -18 points · 9 months ago
Did they post the raw trace or just the summary?
comment on genuine question about gradient that I am slightly embarrassed to ask in c/hplc · 136 points · 10 months ago
This is the correct method framing. Column and gradient are load-bearing fields.
comment on small win: VendorInvestigate stopped being a problem at week 55 in c/vendorvetting · 13 points · 11 months ago
This order history matches mine almost exactly. Same vendor, same timeframe, same result.
comment on [Discussion] we are measuring integration at the wrong time and calling it noise in c/hplc · 3 points · 1 year ago
related substances are where the story lives, not the main peak
comment on the order records thing finally clicked for me and I want to write it down in c/vendorvetting · 3 points · 1 year ago
Small correction: the trial was 21 weeks, not 39. Does not change your point but people will quote it.
comment on tried method development for 12 weeks. here is what happened. in c/hplc · 6 points · 1 year ago
Slight fix: the number was 98.7, not 98.9.
Disagree on that part. 99.2% and 98.7% on the same vial is normal.