Chromatography Forum

Hello all-

I'm currently extracting waste oils and raw materials and running PCB screens on them.

I've read on another site that isooctane is more suitable for extraction because of it reduces error due to solvent volatilization.

Can anyone in here verify this? I've been using hexanes from Fisher. I haven't seen any problems, but if I can improve my extraction process, that would be a plus.

Thanks,
CW

You are correct that isooctane aids what I would call handleability of your extracts over hexane.

First, from a personal safety perspective, your exposure is lower simply because of the lower volatility. Check the MSDS, and if my recollection is correct, the health issues are somewhat less with isooctane.

From the analytical perspective, once in your vial both will stay put just fine (so long as you're using the typical Teflon backed septum and they are crimped correctly) but once pierced, if you re-use the vial, you will find that the hexane will have concentrated significantly more than the isooctane.

This was particularly true on some of the older GC's where the tray sat above the injection port. With most current designs, the tray is fairly removed from the instrument so you don't have the level of heating you used to need to deal with.

Greg