Page 192 - Illustrated Pocket Dictionary of Chromatography

T

tailing A condition in a chromatographic elution profile where the
peak distribution is skewed after the peak maximum (see asymme-
try). Mathematically, tailing is quantitated through the use of an asym-
metry factor. Tailing is often due to one or more of the following:
nonideal equilibria between the mobile and stationary phases (i.e.,
nonlinear isotherms), slow kinetic desorption from the surface, leaks,
voids at the top of the column, column bed imperfections, or pockets
of dead volume in the system.
tailing factor, T Related to the asymmetry factor but explicitly
defined in the US Pharmacopoeia as:
T 0.05 = w 0.05 2 w a

The tailing factor was
developed by the USP as
a parameter to define
peak symmetry. The
appropriate equation and
place on the peak to
determine T is shown
above.
Illustrated Pocket Dictionary of Chromatography, by Paul C. Sadek.
ISBN 0-471-20021-2 Copyright © 2004 John Wiley & Sons, Inc.
195