Chromatography Forum

Hi, can someone please tell me where to find the information about differences in columns prepared from sol and sil gel methods, or possibly even explain
Many thanks
Liv

Well, I have always had problems with this nomenclature, and I ended up making fun of this ("jolly gel and silly gel").

The real story about differences in silicas is the silica purity. Older silicas are made from a raw material that goes ultimately back to sand. The consequence is that these silicas contain a reasonable amount of metal ions, such as aluminum or iron, which are defects in the structure and are the reason for acidic silanols on the surface. Modern silicas are made from tetraethoxysilane as the precursor, which results (together with other precautions) in the creation of high-purity silicas, which do not have these acidic sites on the surface. The consequence of this is that reversed-phase packings can be created from high-purity silicas that show much less tailing than is possible with the older silicas.

In this context, the "silly gels" are the old impure silicas, and the "jolly gels" are the modern high-purity silicas...

Thank you so much for replying to my questions. I have gotten your book and would like to say that it is really informative, and is helping me loads
Once again, Thank you very much
Liv

UWE,

My impression for these two terms is that sil gel refers to the silica made with silicate as the starting material and sol gel refers to the silica made via the sol-gel method (from tetraethoxysilane). Both methods can produce high-purity silica but with different particle structures. Can you comment as I might be mistaken.

Thanks,

The sol-gel process is a defined process how one proceeds from a solution to a solid gel. You can do this starting with water glass or with a high-purity silane. It does not imply anything about the raw material or its quality.

http://www.chemat.com/html/solgel.html

http://en.wikipedia.org/wiki/Sol-gel

A sil-gel process does not exist.

Thanks for the information and clarification.