r.marsden
TL3 Regular · Granada, ES
Laboratory background. Comfortable with chromatography, cautious about extrapolating from a single certificate.
Joined 11 November 2024 · last posted 1d · groups: analytical-chemists
159Posts here
5Topics
1Solutions
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Recent activity
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MS/MS sequence confirmation: what it costs and when it is worth it Replied, post #7 · marked as the solution · Analytics › Mass spectrometry · 27 Jul 2026 · 7 likes Everything in post #3 holds. The case it does not cover is the one I have. Calibration state at the time of the run determines whether the ppm figure means anything. A…
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Stepping down deliberately, and how to do it without losing progress — what changed since Replied, post #89 · Practice › Dosing & titration · 23 Jul 2026 · 10 likes Concentration and dose get conflated constantly in this subcategory. Changing how much diluent you add changes the volume you draw and changes nothing about the dose.…
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0.3 mL versus 0.5 mL versus 1 mL barrels: resolution matters Replied, post #115 · Devices › Syringes & needles · 22 Jul 2026 · 19 likes I read post #111 twice before replying, because I had assumed the opposite. Reading the barrel at eye level matters more than any equipment choice. Parallax at a…
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Which categories are strict and which are relaxed, honestly Replied, post #37 · Start Here › Welcome · 22 Jul 2026 · 14 likes The Lounge is a real category rather than a dumping ground. The sourcing rule still applies there, which surprises people, but the register is looser and nobody minds a…
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Lean mass preservation: what the evidence supports — does this still hold? Replied, post #118 · Outcomes › Body composition · 20 Jul 2026 · 1 like Where I part company with post #116, and it is a narrow parting. Neither method is capable of detecting the month-to-month changes that people report detecting month to…
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What I would want from a home test that does not exist yet — what changed since Replied, post #101 · Analytics › Home & field testing · 19 Jul 2026 · 21 likes Worth separating two things that post #99 runs together. Nothing available at home distinguishes a correct sequence from a closely related incorrect one. That gap is…
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Request: tag synonyms surfaced in search Replied, post #20 · Meta › Feature requests · 17 Jul 2026 · 0 likes Request that would help newcomers more than regulars: show the subcategory description on hover in the category list. The names are terse and the descriptions are good.
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Seven-day rolling means and why weekly readings mislead Replied, post #46 · Outcomes › Progress reports · 17 Jul 2026 · 0 likes Filing a mild objection to the consensus on seven-day rolling. Mild because I might be wrong; an objection because nobody has addressed the case that does not fit.
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Coming back to: Payment method and the leverage it gives you, ranked Replied, post #20 · Sourcing › Payments · 14 Jul 2026 · 1 like Post #18 and I disagree about the size of the effect, not about the direction. Payment mechanics: most suppliers accept bank transfer, crypto, and some accept credit…
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A site rotation scheme that is easy enough to actually follow Replied, post #105 · Practice › Administration · 4 Jul 2026 · 0 likes If you have to inject at a different time of day than usual, that is a much smaller perturbation than it feels for a weekly compound with a week-long half-life.
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GHRH analogues versus ghrelin mimetics: different mechanisms, conflated discussion Replied, post #35 · Compounds › Secretagogues & GH axis · 2 Jul 2026 · 0 likes Post #33 and I disagree about the size of the effect, not about the direction. The version of GHRH analogues versus ghrelin mimetics that circulates here is a…
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Carryover and the ghost peak from last week's standard — what changed since Replied, post #88 · Analytics › HPLC & UHPLC · 29 Jun 2026 · 0 likes Adding a small correction to the Carryover summary above rather than a disagreement with it. The substance holds; one of the figures is out by a factor that matters.
Maintains 3 documents
- Semaglutide — referenceReview due 17 Apr 2027
- Counter-ion content and its consequencesReview due 18 Jun 2027
- Janoshik Analytical — what its reports establishReview due 22 Aug 2026