Chromatography Forum

Good morning, all.

I am still in the planning stages of a purchase of an HPLC. I would like to capture aliquots of material, as they come out of the column, then concentrate them for further analysis on an HPLC. For dissolved resins (acrylics, alkyds, etc.) in a GPC or reverse-phase system (depending on how I need to perform the tests), what would be a good, robust, quiet system for concentration? In the past, I've used vacuum centrifuges for biochemistry/genetics research, but the eppendorf tubes which are utilized are likely too small and I am unaware of systems that could handle larger volumes.

Has anyone performed similar work that could weigh in on this?

Thanks!

Hello

What wil be the typical volume of your fractions an what eluents are you going to use?

best regards
Chris

Hi, Chris.

I believe the initial volume would be around 4 mL, at max, or 2 mL as typical. Solvent mixture will typically be water/acetonitrile, I expect.

Thank you

I have successfully collected plant compounds from HPLC in fraction volumes ranging from 1 mL to 25 mL. The fractions were collected in plastic tubes of appropriate volume then placed immediately in a -80 freezer. At that temperature the acetonitrile/water (25:75) from the HPLC freezes solid. The next step I used was to lyophylize (freeze dry) the samples. This only works for compounds that are nonvolatile in a freeze drier.

I have successfully collected plant compounds from HPLC in fraction volumes ranging from 1 mL to 25 mL. The fractions were collected in plastic tubes of appropriate volume then placed immediately in a -80 freezer. At that temperature the acetonitrile/water (25:75) from the HPLC freezes solid. The next step I used was to lyophylize (freeze dry) the samples. This only works for compounds that are nonvolatile in a freeze drier.

You can also separate your ACN/water by adding magnesium sulfate and centrifuge. Not as harsh as lyophylizing.

Thanks, all. My lab lacks lyopholization capabilities, and the magnesium sulfate partitioning may prove to be beneficial, when needed. What G-force do you typically run on your materials? I only have an old (1950s) medical centrifuge that spins at ~ 2000 RPM. Not a lot of force on this guy.

I was looking at some Nitrogen blowdown units or vacuum centrifuge units from labconco, as well. Has anyone had experience with them with respect to HPLC captured samples? How well did they work and what systems were you using them on?

Nitrogen blowdown: http://www.labconco.com/product/rapidva ... systems/66

Vacuum Centrifuge: http://www.labconco.com/category/vacuum-concentrators

Thoughts?

Thanks, all. My lab lacks lyopholization capabilities, and the magnesium sulfate partitioning may prove to be beneficial, when needed. What G-force do you typically run on your materials? I only have an old (1950s) medical centrifuge that spins at ~ 2000 RPM. Not a lot of force on this guy.

I was looking at some Nitrogen blowdown units or vacuum centrifuge units from labconco, as well. Has anyone had experience with them with respect to HPLC captured samples? How well did they work and what systems were you using them on?

Nitrogen blowdown: http://www.labconco.com/product/rapidva ... systems/66

Vacuum Centrifuge: http://www.labconco.com/category/vacuum-concentrators

Thoughts?

I recommend doing the best that you can with the centrifuge that you have. The longer you spin, up to a point, the drier your solvent will be.

Whichever nitrogen blowdown apparatus you choose to use, be sure to add plenty of heat.

I have never used the vacuum concentrator.