Chromatographic Terms and Parameters

Mobile Phase and Stationary Phase Mobile phase and stationary phase are standard terms used in chromatography, including HPLC. The mobile phase is the 

Physical Chemistry of Macromolecules Basic Principles and Issues, Second Edition. By S. F. Sun ISBN 0-471-28138-7 Copyright 2004 lohn Wiley Sons, Inc. 

Retention Retention R is defined as the equilibrium fraction of the sample in the mobile phase hence, 1 R is the sample equilibrium fraction in the stationary phase. The ratio of R over 1 — R is expressed by 

This is the classical equation derived by Martin and Synge (1941). Equation (13.3) can be extended to the form 

Among the parameters described, the most frequently used in HPLC are Vr, (r, and k. The parameters Vr and (r are further related by a factor F, the flow rate in milliliters per second of the mobile phase through the column  

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