Retention time variability according to USP

[dimi]

Hello to all,

Does anyone know what is the maximum allowed variability in a compounds retention time according to USP for an HPLC method? This is not clear on the USP general chapter <621>, though some analysts I've read report +/- 10% on the target value.

Or it can only be determined through method development or by means of robustness?

Thank you in advance for your responses

[Consumer Products Guy]

I would regard any retention times in USP, a publication, or a technical application as a guideline only. With USP especially, the brand of column is not even detailed, plus there are differences in plumbing among the HPLC instruments.

Now, your retention time REPRODUCIBILITY/REPEATABILITY with your column and your instrument is entirely different. We typically exceed the target of +/- 2% RSD by a large margin.