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column equivalency
Posted: Thu May 14, 2009 2:42 am
by mohan_2008
Is there a way to assume column equivalency and substitute on column for an other.
The QA department is asking for a very valid answer with proof.
For eg:
Zorbax SBC8 4.6x150 mm 5 uM is equivalent to:
These Morons think that column equivalency means:
exactly the same dimensions (such as any C8 column with the same dimensions).
Posted: Thu May 14, 2009 3:17 am
by Don_Hilton
Would it help to explain that the column selection is performance based and that the vendors use proprietary processes and materials in the manufacture of the colmn packings?
It is sort of like buying a 30 year old bottle of Scotch. Basically a mixture of water and ethanol (with some traces of other stuff in there). Small differences - but a world of difference.
Posted: Thu May 14, 2009 10:14 am
by scottythree
You may want to refer to USP Chapter <621> Chromatography. I do know there is a section in there under System Suitability and it list several changes that may be applied (for USP test methods though).
Posted: Thu May 14, 2009 1:35 pm
by DR
Go through the catalogs of other column suppliers - they will frequently offer direct comparisons between a given (SB or other specific type) packing and their own version (Grace, Phenomenex are examples of catalogs that do lots of this). You will probably have little trouble finding comparisons involving some at least vaguely similar molecules to what you're working with. Start there, trying out some columns of the same dimensions. If they meet your method's suitability requirements, use the heck out of a couple (from different lots) - if they perform well over the same time frame that you've been able to use the original column for, you've got it.
Fortunately for you, Zorbax SB is one packing that nearly everyone wants to offer a direct repalcement for.
Posted: Thu May 14, 2009 2:07 pm
by zokitano
How about to forward this link to your QA department:
http://www.usp.org/USPNF/columns.html
Regards
Posted: Thu May 14, 2009 4:42 pm
by Uwe Neue
Column "equivalency" is actually a can of worms. If you have a complex separation, say an impurity profile with closely eluting analytes, your chances are slim to none to find an equivalent column. If you are doing a USP procedure for content uniformity, with one peak and one internal standard, nearly every reversed-phase column will work for you. The rest of the world is in between. The software selectivity tools (like Lloyd Snyder's tool at the USP website) can help you in selecting something that has a good chance of success, if your method is not extra-ordinarily complicated.