Chromatography Forum

We will soon start using Daicel columns on our SFC. The problem with this is that when the SFC is shutdown for the night (to save carbon dioxide), the column essentially remains mostly dry in the system (which is obviously not recommended). The current solution to that is to take off the column, install it on our HPLC and flush it with IPA overnight (cannot use the SFC with modifier = 100 % due to the possibility of getting IPA in the SFC pump).

Obviously, this is a bit of an inconvenience, especially if the HPLC is in use or if different solvents than IPA are installed.

One solution would be to get a separate isocratic HPLC pump, but that is rather expensive for an educational facility such as ourselves...

Any suggestions...?

IPA is way too viscous for most cheap low pressure systems to push through a column. Are you sure you need it at 100%?.

If it was a normal phase column, I'd use hexane:IPA, or, if reverse phase, acetonitrile ( or methanol - if recommended ) for overnight weekend storage.

That way, you could use either a cheap low pressure pump, or an old larger stainless steel HPLC column filled with the solvent connected in series ( vertically ) with the column and the liquid pushed through with the CO2, or N2 using a needle valve on the bottom of the reservoir.

Please keep having fun,

Bruce Hamilton

One possibility is a pump from Eldex:

http://www.eldex.com/products/recipro/recipro.htm

One of their HP Models, which are in the range of $1500-2000 (USD), should fit your needs.

Regards,
Dan

Alternately, simply beg, borrow, steal, or purchase an old but reliable stand alone HPLC pump. Something like a Waters 510 or even 600e should suit well. They're everywhere, they don't break, parts abound, and used ones are cheap.

Why not just leave the column dry? Is there any scientific justification for needing to keep some kind of liquid on a column? I'm sure the material is stored as a dry solid before being packed.

So, I guess I'm suggesting that you probably don't need to pump anything through after your carbon dioxide.

I've been using Daicel columns on our analytical and prep SFC system for years. After use I disconnect from the system, letting the CO2 vent off, cap and put in the drawer. Any issues I've had with the columns has been related to the samples purified on them. Typical lifetime for a preparative column is often on the order of one to two years.

I've been using Daicel columns on our analytical and prep SFC system for years. After use I disconnect from the system, letting the CO2 vent off, cap and put in the drawer. Any issues I've had with the columns has been related to the samples purified on them. Typical lifetime for a preparative column is often on the order of one to two years.

Can you tell me what types of Daicel analytical columns you have done this safely with...? I'm inquiring, because when I asked Chiral Technologies about this, they told me that leaving the columns dry out (as in overnight on the SFC) would be a bad idea...


Thanks,

Roxanne.