Thank you for making it very clear that you are running a bare silica column.

DMSO won't damage the column, but it may affect the resolution.

If DMSO acts as a "stronger" solvent than your mobile phase, it will tend to "drag" your compound through the column, sometimes with little interaction with the stationary phase. You may find that small injections work well, but larger injections show a loss of resolution. Try a small injection first, then inject increasingly larger volumes until the resolution is the limit for your chromatography.

Something else that may occur is that your mobile phase may not be able to carry the full injection volume, leading to broad peaks due to solubility limits. Again, starting with a small injection volume, and increasing the injection size will allow you to see the effects.

My experience so far has been with C18, where DMSO injections are somewhat common. The poster link below, although discussing peptides, demonstrates the effects of DMSO as a dissolution solvent for C18; the pictures in the top-center are images of what happens inside a column:

https://www.teledyneisco.com/en-us/liquidChromatography/Chromatography%20Documents/Posters/Pre-Purify%20Peptides%20with%20Flash%20Chromatography.pdf#search=peptide

Thank you for making it very clear that you are running a bare silica column.

DMSO won't damage the column, but it may affect the resolution.

If DMSO acts as a "stronger" solvent than your mobile phase, it will tend to "drag" your compound through the column, sometimes with little interaction with the stationary phase. You may find that small injections work well, but larger injections show a loss of resolution. Try a small injection first, then inject increasingly larger volumes until the resolution is the limit for your chromatography.

Something else that may occur is that your mobile phase may not be able to carry the full injection volume, leading to broad peaks due to solubility limits. Again, starting with a small injection volume, and increasing the injection size will allow you to see the effects.

My experience so far has been with C18, where DMSO injections are somewhat common. The poster link below, although discussing peptides, demonstrates the effects of DMSO as a dissolution solvent for C18; the pictures in the top-center are images of what happens inside a column:

https://www.teledyneisco.com/en-us/liquidChromatography/Chromatography%20Documents/Posters/Pre-Purify%20Peptides%20with%20Flash%20Chromatography.pdf#search=peptide

Hello Mira,

I agree to the previous speaker. In addition I recommend you to think about a special injection technique (At-Column-Dilution).

http://www.waters.com/webassets/cms/library/docs/71500078010rA_AppNotes.pdf

Regards

Markus

Thank you for fast answers. I will try Small injection volume today. The column have dead volume about 100mL so I think 1 to 2 mL of DMSO should be fine. I would do dry-loading method, but we dont have cartridge that can't hold that much pressure typically 100-200 bars.

Even that "small amount" of DMSO might make a difference. The images below are of a 150g C18 flash column. The samples are water soluble dyes dissolved in DMSO. The 1024 image (top) is the mixture dissolved in DMSO and run, The 1060 image (bottom) is something I term "On-column Dilution", where the hardware doesn't need to be altered. The blue dye should elute much later than the yellow, as depicted in the 1060 image.

To do this:

I'll be presenting this at the spring ACS meeting. I also have data for C18 prep HPLC.