Limit for RT during analysis

[Sunjay]

Dear All,

We have one SOP on HPLC analysis which states that
The RSD for the initial 5/6 system suit injections should not be more than 0.5%.
We want to add some criteria for the Retention Time (RT) during the sample analysis.

For example: The % differnce of the RT during sample analysis should be with in X % to that of the initial sys suit injection RT mean.

Is there any referance available for this with you, that what limit can be given to 'X'. If we set it 5%, would it be acceptable to auditors?

Pls share your views or any referance available.

Thanks

[tom jupille]

As far as I know, there is no reference to an overall "acceptable" value. You can set any value you want, so long as you can demonstrate that it does not compromise the specificity of the assay (i.e., demonstrate that no other compound likely to be found in the sample elutes within that window).

That said, I doubt than an auditor would question a value of ±1%. I think ±5% might raise some questions unless you have justification.

[Roy]

We normally do (+, -) 2% of % RSD on RT. I believe agencies will be fine with 2% RSD's on RT.

Thanks

[Sunjay]

We normally do (+, -) 2% of % RSD on RT. I believe agencies will be fine with 2% RSD's on RT.

Thanks

Do anyone has any experience with this?
Can any regulatory guy put some light on this limi?


Thanks/ regards

[rc_12321]

As for as myknowledge is concerned no regulatory body has ristriction on RTs but it is up to us to have valid rt changes.Although no criteria has been set to interpret shifts in RTs it can be easily understood from one s experience that if your RT is very low let us say 5min one can easily expect 0.1 to 0.2 min variation in analysis and i think that is acceptable.
If your RT is more say 20 min i think a variation of .3 to 0.5 is acceptable.
In case of RS analysis where you can use gradient programmes change in RT s may be more when you compare with the isocratic one.IF you have a standard peak at ,say 45min, in gradient programme ,i think ashift about 1min to 2.5min isacceptable.
During calibration of HPLC system we generally calculate % of RSD of RT s also.Quite interesting thing is that During calibration we generally get RSD of 0.0% to 0.1%.When it comes to regular analysis that much accuracy we cannot expect may be because that we use single solvent i.e methanol or acetonitrile as mobilephase where as combination buffer and solvents will be used during regular analysis .This different combination may cause some shifts inRT s.

[amaryl]

A variation in RT reflects the chromatographic parameters such as mobile phase composition (% B, pH ), temperature, flow rate, use of different column, solvents chemicals, different HPLC equipment (for ruggedness) affecting your separation. RT is a parameter to qualitative identification of analyte. Analyzing a single analyte may provide you wider range of variation in RT but your method is less rugged and robust. A variation of +/- 0.1 min makes your method more robust and easily transferable to other labs (rugged) with reproducible results.

In case of impurity profile and stability studies a more strict control in variation of RT is needed.

As stated by sir Tom jupille you need to justify for keeping a broad range of 5 % RSD. Other validation parameters won't hold good.

Refer LCGC article over Retention time changes.

Regards,

Amaryl.