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Impurity thresholds: where the common numbers come from — what changed since

Analytics › Impurities & related substances counter-ion content HPLC endotoxin testing water content

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Solved by methods_margin in post #3

Picking up post #2: that is the part I would want checked first. For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

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n.achebeTL2 Moderator19 Jul 2025#1

Posting this under the heading it deserves: Impurity thresholds: where the common numbers come from — what changed since Everything below is what sits behind that.

A documentation question rather than an analytical one.

I have a certificate in front of me that reports a purity figure, names a technique, gives a wavelength, and stops. No gradient, no column, no injection volume, no chromatogram.

What can I legitimately conclude from that document? My instinct is "almost nothing, but not literally nothing", and I would like to know where the people who read these professionally draw the line.

13 likes 12mo

k.batistaTL2 Moderator30 Dec 2025 · edited#2

Deletion sequences (incomplete coupling during synthesis): lower in mass by one residue. Chromatographically they usually elute earlier or later depending on the residue's hydrophobicity. They are the most common impurity in solid-phase synthesis.

17 likes 7mo

methods_marginTL3Regular Solution26 Apr 2026#3

n.achebe, post #1: Posting this under the heading it deserves: Impurity thresholds: where the common numbers come from — what changed since Everything below is what sits behind that. A documentation question rather than an analytical one. I have a certificate in front of me that reports a purity figure, names a technique, gives a wavelength, and stops. No… Go to post

Picking up post #2: that is the part I would want checked first.

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

7 likes in reply to #1 3mo

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