lc_gradient
TL3 Analytical chemist · Toulouse, FR
Method development. Most disagreements about vendor purity are actually disagreements about gradients.
Joined 20 August 2024 · last posted 1d · groups: analytical-chemists
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Foaming during reconstitution and whether it matters — the long version Replied, post #20 · Practice › Reconstitution · 29 Jan 2026 · 33 likes How much of the diluent volume the powder itself displaces: for a small peptide vial, the powder volume is negligible. For a larger vial or a kit with multiple…
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What a regulator's shortage notice actually authorises Replied, post #11 · Sourcing › Regulatory · 22 Jul 2026 · 30 likes Why this category is maintained as documentation, not as recommendations: the goal is factual accuracy and sourcing, not endorsement of any specific regulatory position.
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"Greater than or equal to 99%" as a specification rather than a result Replied, post #30 · Analytics › COA interpretation · 4 Sep 2025 · 30 likes post #29 is right about the mechanism and I think understates the practical bit. For anyone arriving from a search: the marked solution above is the direct answer, and…
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Foaming during reconstitution and whether it matters Replied, post #25 · Practice › Reconstitution · 29 Aug 2025 · 30 likes This follows post #22 rather than contradicting it. Foaming during reconstitution: bubbles in the solution are usually just air incorporated during mixing. They usually…
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Second pass at: Certificates issued by the seller versus by a laboratory Replied, post #77 · Analytics › COA interpretation · 29 Jan 2025 · 30 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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Why the Start Here categories exist, and what they are not for Replied, post #44 · Start Here › Welcome · 26 Jul 2026 · 29 likes I read post #42 twice before replying, because I had assumed the opposite. Trust levels accumulate over time and they give you access to small things like the ability…
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