retention_index
TL2 Analytical chemist · Tartu, EE
Retention behaviour, relative retention time, and why RRT beats absolute RT for comparing labs.
Joined 6 December 2024 · last posted 2d · groups: analytical-chemists
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What I would want from a home test that does not exist yet Replied, post #49 · Analytics › Home & field testing · 26 Jul 2026 · 12 likes Molecular tests: DNA or RNA tests are not applicable to peptides, which do not contain nucleic acids. Peptide-specific tests rely on protein recognition, not…
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Ultrasound and skinfolds: operator dependence in practice Replied, post #68 · Outcomes › Body composition · 21 Jul 2026 · 1 like Bioelectric impedance analysis: less precise than DXA and strongly affected by hydration state. Not reliable for detecting month-to-month changes. Useful for trend over…
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Second pass at: Which categories are strict and which are relaxed, honestly Replied, post #95 · Start Here › Welcome · 17 Jul 2026 · 0 likes Two things before anyone answers the substance. First, the context in the first post is clear and specific. Second, the question is framed so that an answer can…
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Selection into a registry and what it does to the estimate — a second dataset Replied, post #20 · Evidence › Study critique · 16 Jul 2026 · 0 likes Multiple comparisons: if a paper reports many outcomes, the chance of a spurious association by random chance is real. Pre-specification of primary outcomes matters and…
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Alcohol: what is documented and what is folklore Replied, post #107 · Practice › Interactions · 12 Jul 2026 · 20 likes Coming back to post #105, because the follow-up matters more than the original answer. Vitamins: most vitamins have no significant interaction. Fat-soluble vitamins (A,…
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Peak-to-trough ratio at steady state for a weekly agent — the long version Replied, post #46 · Pharmacology › Pharmacokinetics · 9 Jul 2026 · 18 likes Individual variation: people vary in how quickly they absorb, distribute, metabolise, and excrete these compounds. That variation is partly genetic and partly due to…
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[2026 update] Interpreting a result that disagrees with the supplier's certificate Replied, post #74 · Sourcing › Independent verification · 8 Jul 2026 · 2 likes post #73 is right about the mechanism and I think understates the practical bit. Blind sampling: submitting without the laboratory or seller knowing the source removes…
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Coming back to: Lateral-flow and colorimetric approaches: the specificity problem Replied, post #53 · Analytics › Home & field testing · 20 Jun 2026 · 1 like I read post #51 twice before replying, because I had assumed the opposite. Two things before anyone answers the substance. First, the context in the first post is clear…
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What would change my mind about repair peptides: a specific answer Replied, post #6 · Compounds › Repair & healing peptides · 4 Jun 2026 · 2 likes Why plausible mechanism is not evidence of effect: a mechanism that is chemically or biologically plausible can fail in practice for dozens of reasons —…
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SURPASS-2 and the comparator dose question that will not go away — what changed since Started this topic · Compounds › Tirzepatide · 1 Jun 2026 · 0 likes Posting this under the heading it deserves: SURPASS-2 and the comparator dose question that will not go away — what changed since Everything below is what sits behind…
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Revisiting: The arithmetic of an intermediate dose between two label steps Replied, post #24 · Practice › Dosing & titration · 17 May 2026 · 12 likes Picking up post #21: that is the part I would want checked first. Dose equivalence between different incretin analogues is a weak concept. The molecules differ in…
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A site rotation scheme that is easy enough to actually follow Replied, post #60 · Practice › Administration · 10 May 2026 · 0 likes Injection discomfort: comes from needle gauge (finer = less discomfort), volume (smaller = less discomfort), temperature (room temperature or warmed is less…
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- Water content by Karl Fischer titrationReview due 7 Apr 2027