Chromatography Forum

Hi all,
I have been using oasis HLB comun to concentrate exudates from roots and the column was blocked I was trying to rinse with methanol or water but is impossible...
what should i do?
Thanks

Please provide more information: mobile phase, sample solvent, etc. Was the sample clear, i.e. no solids? What was the flow rate (I assume you use a 2.1 mm x 2 cm column)?
The more I know, the better I can guess what has happend and give advice how to solve the problem.

ok, thanks.

The flow was 10ml/min and sometimes a little up. the column is 5 cmx 2 cm. I passed meoh after water and after the sample that I wanted to collect. I couldn´t collect all the sample because the column was blocked I have tried wahs with meoh or water but it is impossible
thanks

You washed with water, then with methanol at 10 mL/min or more. Then you loaded the sample, right? What was the sample solvent? Then you wanted to elute with methanol, and you got high backpressure. Did you get this high backpressure at 10 mL/min, or at a lower flow rate? How high was it, at which flow rate with what solvent?

By the way, why are you running at such a high flow rate on a 2 mm column? What was the backpressure?

Is it an analytical column or a solid phase extraction column (SPE) that we are talking about here ? The dimensions and flow rates indicate SPE, so there is probably a layer of solids stuck at the top of the bed.

Peter

Hi all,
I have been using oasis HLB comun to concentrate exudates from roots and the column was blocked I was trying to rinse with methanol or water but is impossible...
what should i do?
Thanks

I see only one problem that could occure here. It's only about cleariness of extract. you should filter it through simple paper filter. Or, for better recovery, centrifuge it, to get all particles of unwanted garbage on the bottom. that's it i think.

hope this will help

one more thing. HLB oasis is quite expensive stuff. u can get the same effect on cheaper Strata X polimeric SPE. not worse at all, but twice cheaper.

Zydrunas,
You get what you pay for. Among other things, Oasis does bleed much less junk (=polymer oligomers) into your sample than other materials. It has been designed this way from the beginning...

Can you, and did you, wash this thing by running it backwards?
You may need a better cleanup than passing the sample through a paper filter. There are trillions of examples here on cleanup.

it may be contain colophony in exudates from roots , so it block you HLC column