ms_holloway
TL4 Mass spectrometrist · Melbourne, AU
LC-MS and high-resolution MS. Mass accuracy is a tool, not a verdict. Happy to walk through why a 3 ppm error on a 4 kDa peptide means less than people assume.
Joined 22 May 2024 · last posted 9h · groups: analytical-chemists, wiki-editors, trust-level-4, newcomer-guides
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The SOUL trial and oral semaglutide cardiovascular outcomes Replied, post #3 · Compounds › Oral incretins · 28 Jul 2026 · 5 likes Thank you for the correction. I have edited my earlier post with a note rather than silently, so the thread still makes sense to read. The error was mine and it was the…
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Follow-up: Prior authorisation: what the criteria usually require Replied, post #96 · Access › Insurance & coverage · 25 Jul 2026 · 6 likes Prior authorisation: pre-approval requirements and how to satisfy them. Most denials cite specific criteria. Understanding the criterion is the first step in satisfying…
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How shortages have affected compounding permissions Replied, post #66 · Access › Shortages · 24 Jul 2026 · 8 likes Compounding during shortages: some jurisdictions allow pharmacy compounding when a marketed product is in shortage. That permission is jurisdiction-specific and…
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Seven-day rolling means and why weekly readings mislead Replied, post #98 · Outcomes › Progress reports · 24 Jul 2026 · 2 likes I read post #96 twice before replying, because I had assumed the opposite. Practical note that does not fit anywhere else. Whatever you conclude from this topic, write…
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Coming back to: Batch date after test date, and other internal inconsistencies Replied, post #23 · Analytics › COA interpretation · 24 Jul 2026 · 0 likes A certificate of analysis is a statement by its issuer that a defined test was performed on a defined lot and produced a defined result. That is all it is, and it is…
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Reading order for a first week here, and what to skip until later — what changed since Replied, post #69 · Start Here › Welcome · 22 Jul 2026 · 16 likes The moderation log is public. Every staff action is logged with the rule cited and the reasoning stated. If you get moderated, the explanation is there and it is worth…
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Journal club: what we got wrong in an earlier session Replied, post #105 · Evidence › Journal club · 21 Jul 2026 · 22 likes I read post #103 twice before replying, because I had assumed the opposite. SELECT (N Engl J Med 2023): Semaglutide cardiovascular outcomes without diabetes. The first…
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Historical amylin analogues and what happened to them Replied, post #34 · Compounds › Cagrilintide & amylin analogues · 20 Jul 2026 · 25 likes This follows post #31 rather than contradicting it. Gastric emptying: both amylin and GLP-1 slow it, through partly overlapping but distinct mechanisms. Whether the…
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Second pass at: Sleep apnoea improving and the equipment implications Replied, post #90 · Wellbeing › Sleep · 20 Jul 2026 · 0 likes Sleep quality versus quantity: some people report changes to sleep duration; others report changes to sleep quality without duration change. Both can matter for…
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Coming back to: Batch date after test date, and other internal inconsistencies Replied, post #12 · Analytics › COA interpretation · 14 Jul 2026 · 12 likes When method identifiers are missing: "reversed-phase HPLC" is less specific than "reversed-phase HPLC at 214 nm on a C18 column with a 10 to 40% acetonitrile gradient…
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Endotoxin and why it is a separate question from purity — what changed since Replied, post #76 · Analytics › Impurities & related substances · 13 Jul 2026 · 21 likes Related substances: compounds chemically related to the target peptide but not the target peptide itself. The standard method separates them and reports them as area…
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Coming back to: Reconciling a supplier certificate with an independent result Replied, post #24 · Sourcing › Vendor reports · 10 Jul 2026 · 0 likes On post #20 — agreed on the reasoning, with one qualification. Blind submission is worth the effort: have someone else relabel the sample so neither you nor the…
Maintains 2 documents
- Reversed-phase HPLC for peptidesReview due 10 Jun 2027
- STEP-HFpEF — trial digestReview due 1 Jan 2027