Column phases!

[cody84]

Is there any resource where I can find many different phases explained? Somewhere that is not a supplier?! I'd like to learn the difference between as many phases as I can, meaning for instance what is difference between ODS3 and XDB-C18?
It would also help to learn the difference between actual phases not just manufacturers (ie, CN vs. C8 ).

Thanks in advance!

[Jiri Urban]

Does this help?

http://www.mac-mod.com/pdf/ColumnComparisonGuide.pdf

J.

[cody84]

muchly thanks!

[tom jupille]

If you *really* want to get into it, the best reference I can think of is Uwe Neue's book HPLC Columns: Theory, Technology, and Practice. Here's a link to it on Amazon:
http://tinyurl.com/2e8mhbp

[Rob Burgess]

I concur with cody84 that the profileration and codings used for naming C18 phases in particular is very confusing. Column manufacturers in general don't seem to help themselves with the marketing literature tehy employ - for instance they show "pictures" of polar retentive c18 phases that look exactly the same as their standard C18 fare - all very confusing!

[Gerhard Kratz]

I once found a list of HPLC columns, all modes, on the USP website. But that was only the official definition of L 1 columns for example.
About 3 years ago there was a publication from the university of Paris at the journal of chromatography, comparing most known RP columns. But I agree, what marketing people of most manufacturers create is not very helpful. Alcyl chain of an RP 18 column material with an embedded polar group is not C18. Polymer bonded, or di- or tri-functional bonded is another example. But best is always "total encapping", doubble endcapping or advanced endcapping! That's all marketing. Some manufacturers have internal data with comparative specifications of their own columns and the competition. But difficult to get these data. Some manufacturers often hide more detailed information about the used surface chemistry, some even don't let you know what kind of basic resin they used. Let me know by e-mail if you need more detailed data

[tom jupille]

The naming *is* confusing, but remember that the names are usually given by the marketing people.

More to the point, the actual retention and selectivity behavior of reversed-phase columns (to limit things a bit!) depends on too many factors to be easily encapsulated in a simple name. In fact it takes 5 or 6 numerical parameters to do the job, as witness the selectivity databases on the USP web site (http://www.usp.org/USPNF/columnsDB.html).

Maybe a good analogy is with pharmaceuticals. Do the names "ibuprofen" and "naproxen" provide any hints as to their structure or activity (or anything else, for that matter)? Granted we only have about a thousand or so reversed-phase stationary phases available not millions of organic compounds, but we still have to turn to "knowledge" (on the part of a chromatographer or a pharmacist) backed up by databases and reference information.

This may be a good thing. If it were too easy, they could hire anyone off the street to do chromatography, and we'd be unemployed!



Ibuprofen



Naproxen