% Ret time window for HPLC

[michaelcarolus]

Hi everyone

When using ret time to identify/quantify known or unknown peaks by how much can the ret time of the sample differ from the std. Is 1% a good guide or should this be more stringent. When comparing relative retention times obtained by the USP methods should we also use 1% a guide.

Many Thanks.
MC

[David Blais]

Well, part of that depends on both your internal SOPs and how robust your method is. I think 1% is pretty much universally used, but I'm sure other users on this board may have different experiences. At my company, the ID by retention time is determined by a window of 0.1 minute.

Hope this helps.