Running on a 1260 infinity HPLC vs 1260 infinity II HPLC

Hi b_blackney 

You seem to have checked everything that I would have checked!  Are the differences in resolution because of increased peak width or decreased retention time differences.  Could you post some chromatograms so that we can see the difference?

/Andy

Thanks for responding, the peaks are about the same size so I believe it's a retention time issue. I've been doing some additional research on this and the closest I can find to maybe being the issue is that the delay volume from the infinity I to the infinity II was improved.  So if that's the case it's probably more efficiently switching to the new gradient composition and therefore it's causing the second peak to elute faster than I'm expecting.  If that's the case, I'm not sure what my next path forward will be as I'm in a regulatory field and changing the gradient is not the path I'm hoping for.

Agilent 1260 Infinity (same column):

Agilent 1260 Infinity II (same column):

Hi b_blackney 

If the Infinity II system is an identical module for module change, I wouldn't expect there to be much of a difference in mixing or volumes.

The next question is: can you share the model numbers of the Infinity and Infinity II systems?

/Andy

Hi b_blackney 

If the Infinity II system is an identical module for module change, I wouldn't expect there to be much of a difference in mixing or volumes.

The next question is: can you share the model numbers of the Infinity and Infinity II systems?

/Andy

The 1260 Infinity HPLC has a G1311B Quaternary Pump, G1367E Autosampler, and G1365C MWD.  The 1260 Infinity II HPLC has a G7111B Quaternary Pump, G7129A Autosampler, and G7165A MWD

Hi b_blackney, what you your column compartments? During method transfer the resolution loss often comes from differences in temperatures. What modules do you use in the Infinity and Infinity II for thermostating the columns and what temperature do you use?

Very similar, then!  Could be, as nadjan  suggests, a difference in column compartment.