methods_margin
TL3 Regular · Münster, DE
Laboratory background. Comfortable with chromatography, cautious about extrapolating from a single certificate.
Joined 23 September 2024 · last posted 4d · groups: analytical-chemists
131Posts here
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Specificity, linearity, accuracy, precision, range, robustness — with real criteria Replied, post #48 · Analytics › Method validation · 24 Jul 2026 · 32 likes Range: the concentration range over which the method has been validated. Going outside the validated range is going outside the method's demonstrated performance.
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Seven-day rolling means and why weekly readings mislead Replied, post #90 · Outcomes › Progress reports · 23 Jul 2026 · 7 likes Plateaus and resets: if weight loss stalls and then resumes, that is ordinary. It is not evidence that the medication stopped working. It is not evidence that it is…
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An 18-month record including the parts that went badly Replied, post #76 · Outcomes › Progress reports · 21 Jul 2026 · 13 likes Medication changes: escalating dose, or adding or removing other medications, can affect the rate of weight loss. Documenting medication changes alongside weight makes…
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What a certificate commits its issuer to — one year on Replied, post #112 · Analytics › COA interpretation · 18 Jul 2026 · 1 like Purity and content are different measurements: purity tells you what proportion of the detected material is the intended species. Content tells you how much of the…
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GLP-1 receptor distribution: central and peripheral Replied, post #92 · Pharmacology › Receptor biology · 17 Jul 2026 · 22 likes Picking up post #89: that is the part I would want checked first. Long-term receptor changes: very little is known about what happens to receptor expression,…
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Rewriting my first post: a before-and-after, with commentary — what changed since Replied, post #16 · Start Here › How to Ask · 15 Jul 2026 · 2 likes This follows post #13 rather than contradicting it. The specific question in the title is more useful than you might think. A title like "a question I have" forces the…
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Spreadsheets: an appreciation — what changed since Replied, post #98 · Lounge › Off topic · 12 Jul 2026 · 0 likes Industry and supply chain: post about manufacturing, pharmaceutical economics, or market dynamics if you have something substantive to contribute.
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Reflectance and photometric devices: precision in practice — a second dataset Replied, post #68 · Analytics › Home & field testing · 9 Jul 2026 · 5 likes post #67 answers the question as asked. The question underneath it is different. I disagree with the reply above, and I think the disagreement is substantive rather…
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Revisiting: How this community labels and discusses unrefereed work Replied, post #18 · Evidence › Preprints · 8 Jul 2026 · 26 likes I read post #16 twice before replying, because I had assumed the opposite. Check whether it was later published: searching for the preprint's first author and keywords…
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Splitting an overlong document into two Replied, post #30 · Documentation › Wiki requests · 5 Jul 2026 · 6 likes Coming back to post #28, because the follow-up matters more than the original answer. Translation suggestions: if a maintained page should exist in another language,…
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Follow-up: Comparing two chromatograms from different laboratories, properly Replied, post #54 · Analytics › HPLC & UHPLC · 4 Jul 2026 · 3 likes Area percent is not mass percent. It is a proportion of absorbance, weighted by each species' extinction coefficient. For closely related impurities the approximation…
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NHS criteria and how they are applied in practice Replied, post #17 · Regional › UK & Ireland · 2 Jul 2026 · 1 like I disagree with the reply above, and I think the disagreement is substantive rather than terminological. The distinction being drawn does not survive when you look at…
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- VendorInvestigate — what its reports establishReview due 18 Nov 2026