Spike-and-recover accuracy for a peptide assay posts 121–127

Everything in post #119 holds. The case it does not cover is the one I have.

Accuracy for a purity assay is usually demonstrated by spike recovery across a range. Without a reference standard, that is exactly the work that cannot be done, which is why reference material matters.

That is all I can say without guessing.

Second-hand on spike-and-recover accuracy, so weight it accordingly — someone whose method I trust told me this and I have not verified it myself.

Something worth flagging about spike-and-recover accuracy: the strongest-sounding claims in this thread are the ones with no source attached, which is the usual pattern and not a coincidence.

System suitability is the ongoing evidence that a validated method is still performing. Validation is done once; suitability is done every run, and it is the one that appears on a certificate.

Answering the question post #123 raises rather than the one it answers.

The documentation on spike-and-recover accuracy is better than this thread and I say that as someone who has posted in the thread.

The arithmetic in post #123 is right; the assumption feeding it is the part to check.

Reframing spike-and-recover accuracy slightly, because I think the disagreement is about the question rather than the answer. If the question is "does it happen", yes. If it is "how often", nobody here knows.

Where a pharmacopoeial monograph exists, a method that follows it inherits a great deal of assurance. Almost nothing discussed here has one.

If that is already documented somewhere, ignore me and link it.