Message-Id: <199701071947.OAA25476@chem.bu.edu>
Date: Tue, 7 Jan 1997 15:04:09 +0000
From: laursen@bu.edu (Richard Laursen)
Subject: Re: Resolution in Chromatography
To: Recipients of ABRF List <abrf@aecom.yu.edu>
The reason both expressions, alpha-1 and (alpha-1)/alpha are used is that
the value for alpha, in the case of unresolved peaks, is generally very
close to 1.0, and so both equations are essentially equivalent (e.g., [1.2
- 1] is not very different from [(1.2 - 1)/1.2]. Alpha can of course be a
larger number, such as 2 or 10, but if it is that large (all other things
being equal), then you probably have baseline resolution anyway. In other
words, the first expression is an approximation of the second.
Richard Laursen
>I have a theoretical question for all the chromatography specialists among
>the list members.
>During the preparation of a lecture on chromatography I have found two
>different expressions for the calculation of the resolution:
>
>1. R = 0.25 (alpha-1) (square root of N) (k/k+1)
>
>2. R = 0.25 (alpha-1/alpha) (square root of N) (k/k+1)
>
>In both cases the definition of alpha is the same (k2/k1). Can anybody
>explain me if and how these two equations are correlated to each other?
>Which is the "right" one?
>
>
>Many thanks and bets regards
>Peter
>
>
>**************************************************************
>
>Dr. Peter Hunziker
>Universitaet Zuerich
>Biochemisches Institut
>Winterthurerstr 190
>CH-8057 Zuerich
>Switzerland
>
>Tel: +41-1-257 55 20
>Fax: +41-1-363 79 47
>E-Mail: phunzi@bioc.unizh.ch
-------------------------------------------------------------
Richard A. Laursen
Department of Chemistry
Boston University
590 Commonwealth Ave.
Boston, MA 02215
Tel (617) 353-2491; FAX (617) 353-6466
email: <laursen@bu.edu>