Chemistry Forums for Students > Organic Chemistry Forum for Graduate Students and Professionals

Can dry loading be used on reverse phase silica?

(1/2) > >>

Babcock_Hall:
Dry loading has become our preferred technique for normal phase chromatography.  This week we had a C18-coated silica column to run using methanol/water.  Could this have been dry loaded?  I imagine that the ratio of coated silica to crude product will be higher: I recall a suggestion to have a greater ratio of coated silica to product than would be done in normal phase.

Guitarmaniac86:
I've dry loaded on RP silica, it can be done.

rolnor:

I preferre wet-loading, if your sample does not dissolve in the eluent you should change it, for example use toluene instead of hexane. I think generally you get a more narrow band of the sample if you use wet-load and thus better separation. I have never tried dry-loading a RP column.

kriggy:
Im assuming we are talking about some kind of preparative flash system ?
Is it because of poor solubility of your mixture ? Have you tried loading in DMSO or DMF? I load all my RP purifications in DMSO with the method being isocratic in high aq. for first 3-5 minutes to wash away the DMSO

Babcock_Hall:
My department is getting a preparative flash system soon; we just packed a column with C18-coated silica beads.  My student may have used more solvent than was needed, but I am not sure.

Navigation

[0] Message Index

[#] Next page