I got a good TLC separation for my polar fraction with only ACN-Water 9:1. Can I use the same solvent system with silica gel column for isolation? I did a search and ended up with a concept which is new and promising called "HILIC". However, I am not able to fully understand this concept. Can anyone give me a short note on how I can run my fraction with silica column with aforementioned solvent system (if it is at all possible).
"...Also Silica-, Amino-, Diol- and Cyano phases are quite often
used for HILIC separations." http://www.knauer.net/fileadmin/user_upload/produkte/files/Dokumente/columns/lc_columns/guides/KNAUER_HILIC_method_development_guideline.pdf
Sure, you can use this conditions in column chromatography, keeping in mind its lesser resolution.
Check also valuable notes of Jack Silver in related subtopic https://www.researchgate.net/post/Silica_column_for_polar_compounds2
You can certainly try to run this in HILIC mode. I'd be very interested in how it translates. If you know the properties of the analytes in your fraction, you can use that information to modify the mobile phase - I would suggest you add a small amount of buffer - ammonium formate or ammonium acetate at 2 - 10 mM - especially if you know you have some ionizable bases in the fraction. If you want a bit more information on HILIC, I gave a webinar for Select Science recently that you might find informative. Here is a link http://view6.workcast.net/register?pak=5061956691401502
It would be good to know the results of your experiment once you perform column chromatography with the solvent used for TLC. As far as water is concerned, we refrain from using it in column chromatography as it leads to breaking of column. Now if you are using HILIC mode, I would like to know the outcome. Otherwise if you have a very good resolution (as it appears from your question), Why don't you try for a preparative TLC? As you already know the Rf through TLC, you can easily run a prep-TLC and scrap out individual compounds from the plate itself. Although it is conventional yet a very effective method.
Regards
Yes, you can use this solvent system. Some hints to help you:
- Pack the column in 1-2% water to form the hydration layer on the silica if you are running a gradient. If you are running isocratic, just use the mobile phase for your TLC plate
-Dry load the sample. I find that a wet-loaded sample tends to run through the column without interacting with the silica
-You may use acidic modifiers (formic acid, acetic acid, etc), but not basic (ammonium hydroxide). Keep the pH below 7 as silica dissolves in basic conditions in polar solvent systems.
Here's an example of flash chromatography on silica using an acetonitrile/water gradient (Figure 5):
http://www.isco.com/WebProductFiles/Applications/101/Poster_and_Paper_Reprints/Strategies_for_the_Flash_Purification_of_Highly_Polar_Compounds.pdf
You can use this solvent system with silica gel column in HILIC mode, however you may ensure that the pH of the system remain below 7 for which acidic modifier can be used as suggested by Jack Silver.
Dear Balaji if you don't mind Could you please give me your mail Id ,
I would like to ask few questions regarding C 18 open column.
Please drop me an email to mine mail Id. [email protected]
- Badges
- Science topic