RRT variation limit

Dear colleagues,

What is the acceptable deviation limit for RRT

Many thanks and regards,
Ilknur

@Ilknur
Use of RRT (relative retention time) is used to reduce the uncertainty due to RT, However the deviations of relative retention time values measured for the test substance from the values obtained for the reference compound should not not be more than values determined statistically from replicate assays of the reference compound
as per USP “Relative retention times may be provided in monographs for informational purposes only to aid in peak identification. There are no acceptance criteria applied to relative retention times”.

Refer:
USP General Chapters: <621> CHROMATOGRAPHY