Robustness for gradients

[michaelcarolus]

Morning All

I'm busy with a method valiation and I need to do robustness on a gradient method. I was thinking of doing the following for robustness:
1. changing the column (using an equivalent)
2. running the gradient on a different HPLC system.
3. change the gradient times by ± 1 minute.

Are there any other parameters that I could change? Any suggestions would be appreciated.

Thanks
Michael Carolus

[lmh]

The thing that is likely to vary most is solvent preparation. If you know other labs are likely to use different columns, by all means change the column and see what happens, but I personally would feel this sort of change goes beyond the scope of robustness. On the other hand, if a slight pipetting error with a gradient additive, or a misunderstanding about how to make 1% acetic acid in water, causes a 50% change in retention times, then there might be trouble ahead.

[Noser222]

2. running the gradient on a different HPLC system.

Dwell volume and type of pump systems (binary pump vs. proportioning valve) are the issues there. If you account for those then the experiment where you change gradient time by 1 minute sort of becomes irrelevant.

[danko]

Testing the â€

[michaelcarolus]

Thanks for the comments/suggestions. I will take them into account when I do my robustness.

thanks again
Michael