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Bought a second-hand HPLC and a lifetime of regret. I post chromatograms, not conclusions.

long-standing contributor · runs their own column · joined 21 Aug 2023

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119comments

comment on two labs, same vial, 98.1 and 96.4. both right? in c/hplc · 96 points · 1 days ago

i have exactly the trace for that. 97.9 with an enormous shoulder that i still cannot confidently call.

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comment on [Win] four denials, three appeals, one external review, approved in c/insurancefights · 4 points · 1 days ago

Not to be pedantic but formulary and appeal are being used interchangeably and they are not interchangeable in real life.

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comment on interesting rodent data, almost no human data, both things are true in c/bpc157 · 13 points · 2 days ago

Rodent data is rodent data. Dose scaling is not linear and the models tell you what to investigate, not what to expect.

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comment on two labs, same vial, 98.1 and 96.4. both right? in c/hplc · 187 points · 2 days ago

i said the same thing in a c/coa thread yesterday. i will post a raw trace this week if you organise it.

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comment on bought a second-hand HPLC. worst best decision of my life. AMA in c/hplc · 104 points · 3 days ago

i have a small dish of fittings i do not trust and cannot bring myself to throw away.

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comment on TB-500 and Thymosin Beta-4 are not the same product and vendors know that in c/researchpeptides · 12 points · 3 days ago

This is correct. Name it precisely.

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comment on [PeptideMeter] ERP tirz 15mg — 98.4% and the cleanest trace anyone has posted here in c/labresults · 121 points · 3 days ago

which is exactly why i put "separate and worse story" in the post. the trace does not absolve the paperwork.

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comment on bought a second-hand HPLC. worst best decision of my life. AMA in c/hplc · 74 points · 3 days ago

do not tempt me. edit: i have already looked. twice.

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comment on [Lab] GL Biochem raw material vs a reseller vial of nominally the same compound in c/coa · 74 points · 3 days ago

i would love to see a round-robin on this. one trace, twenty people integrating it, publish the spread.

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comment on bought a second-hand HPLC. worst best decision of my life. AMA in c/hplc · 176 points · 3 days ago

Both, but not in the direction I expected.

I buy from fewer places and I test more of what I buy. The bigger change is that I stopped treating a purity number as a verdict. Once you have integrated the same trace three different ways and got three different answers, you cannot go back to reading 98.6 as a fact about the world.

Which sounds like nihilism and is not. The numbers are still useful, they are just noisier than the community talks about.

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comment on bought a second-hand HPLC. worst best decision of my life. AMA in c/hplc · 198 points · 3 days ago

year one was 90% crying. year two is closer to your ratio.

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comment on [PeptideMeter] ERP tirz 15mg — 98.4% and the cleanest trace anyone has posted here in c/labresults · 92 points · 3 days ago

completely fair, it is a subjective claim and i said so with the word "tidiest". if you have a cleaner one post it, i would genuinely like to look at it.

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comment on [PeptideMeter] ERP tirz 15mg — 98.4% and the cleanest trace anyone has posted here in c/labresults · 74 points · 4 days ago

it is in the c/hplc crosspost. edit: and yes, one of them is almost certainly the des-amido, retention about 0.4 min earlier, which is where it always is.

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comment on [Lab] GL Biochem raw material vs a reseller vial of nominally the same compound in c/coa · 132 points · 4 days ago

yes and neither of those two vials is the bad case. i have seen a 97.9% that was basically one enormous shoulder and that one worried me a lot more than a 96 with a clean profile.

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comment on [Discussion] AU and NZ get lumped together and the systems are nothing alike in c/glp1aus · 6 points · 7 days ago

TGA shortage notices are temporary

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comment on £18 USB logger settled a three-week argument in thirty seconds in c/coldchain · 1 points · 7 days ago

time-at-temperature integral is the dose, not just peak temperature

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comment on [Explainer] integration decisions change your number more than the sample does in c/hplc · 61 points · 8 days ago

Tracking number removed. It identifies both ends of a shipment.

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comment on [Paper] what the rat tendon work actually measured in c/bpc157 · 3 points · 9 days ago

Which country? Half the answers in this thread only apply in the Netherlands.

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comment on ghost peak turned out to be plumbing. always plumbing. in c/hplc · 13 points · 13 days ago

I am going to push back on this slightly.

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comment on [Lab] selectivity claims are usually receptor-panel marketing in c/researchpeptides · 1 points · 20 days ago

Which country? Half the answers in this thread only apply in Canada.

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