Change Reverse Phase to Normal Phase

[bmoritz]

I hope this hasn't been covered ad nauseum, but we just received an Agilent 1100 and finally got it to work. The AIV was messed up and fixed. So now that it's working we want to use this machine as a normal phase instrument. My question is this

Is there anything special that needs to be done to run normal phase? Can we just hook up some hexanes and start running the instrument?

Thanks in advance.

BM

[mbicking]

In general, an 1100 should work well in normal phase. However, if you intend to use normal phase 100% of the time, then you should switch the pump seals and the seal in the metering device. The rotor seal in the autosampler may also require replacement; check with Agilent to be sure. If you plan to switch back and forth, stick with the reverse phase (standard) seals.

The only other issue is the changeover to normal phase. If you have the older degasser, remember that the internal volume is 12 mL, so you need to pump at least 50 mL of new solvent through. I would recommend that you purge all channels with large (i.e., > 100 mL) volumes of IPA, then follow that with the individual solvents for each channel. If you don't do this, you could see traces of the old solvent bleeding out from the system for many hours. If this is water in your hexane (A) channel, reproducible results will be hard to obtain.

[bmoritz]

mbicking,

Thanks for the suggestion. It's switched over and pumping! Only problem is the hexanes are introducing air bubbles into the quant pump. No air bubbles are seen for IPA, and MeOH lines. I posted a new topic asking for help.

BM