Chromatography Forum

Dear members,
I always use the value of Rs not less than 2 during method development for simple mixture. This value is hard to get when we use more complex mixture (containing 10 or more components). Is it Rs = 1 or 1.5 enough in this case? Thanks in advance.

Regards,
Siswanto

Yes, in cases where it is difficult to get resolution, it will be ok.

I have seen a warning letter, in which the resolution limit was 1 in their STP but their method was capable of giving higher resolution. So the point of USFDA was, the limit should be higher as you method of capable of achieving that.

Regards

As far as I know, Rs > 2 is a "recommendation" in the FDA "Guidance for Reviewers", not a requirement. If your validation results for accuracy and precision are otherwise acceptable, a lower resolution may be OK (and, conversely, a higher resolution may be required!).