Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 3, pp. 352−358.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © G.M. Sergeev, V.P. Sergeeva, E.V. Elipasheva, T.V. Maksimova, P.N. Kulikov, 2012, published in Zhurnal Prikladnoi Khimii, 2012,
Vol. 85, No. 3, pp. 375−382.
OF SYSTEMS AND PROCESSES
Anion Exchange Selectivity: Study of Sorbents with Various
Matrices for Separation of Chlorine Oxoanions
and Chloroacetic Acids
G. M. Sergeev, V. P. Sergeeva, E. V. Elipasheva, T. V. Maksimova, and P. N. Kulikov
Lobachevsky State University, Nizhni Novgorod, Russia
Received December 24, 2010
Abstract—New theoretical approaches to the problem of anion exchange selectivity were formulated for the
example of ion-chromatographic separation of chlorine oxoanions and chloroacetic acids with various sorbents.
Correlation dependences of the retention factor on the molar mass, enthalpy and entropy of hydration, ion radius,
and polarizability of ions were determined.
Despite the wide introduction of selective spectro-
scopic and mass-spectrometric detection methods into
practice of ion chromatography [1, 2], steadily increas-
ing attention has been paid to studies of the ion retention
mechanism and reasons for selectivity.
The separation factor α
, or relative retention
(column selectivity), and resolution R
signals are most important parameters of the
chromatographic process [3, 4]. The value of α
is determined by thermodynamic characteristics
of substances ; it is affected by the nature of
components subjected to chromatographic analysis, and
also by the type of the sorbent and composition of the
eluent. However, a separation factor exceeding unity is
a necessary, but not sufﬁ cient condition for separation
of mixture components, because it does not describe the
quality of the separation process. The resolution R
two chromatographic peaks takes into account not only
their positions, but also peak widths. It should be noted
that a wide variety of factors affects the selectivity of an
It has been reported  the selectivity can be provided
in anion exchange by optimization of such characteristics
of functional groups of quaternary ammonium bases as
linear dimensions, volume, and hydrophobicity of alkyl
radicals. The ion-exchange selectivity was considered in
 in terms of inner-diffusion processes. It is believed 
that a common feature, formation of an induced cation–
anion pair in the sorbent phase, is inherent in various
types of ion chromatography: ion exchange, ion pair, or
zwitterion (electrostatic). Therefore, the selectivity is
deﬁ ned as the relative capacity of ions to form pairs of
this kind. It has been shown  that effective separation
is only possible if competitive sorption mechanisms are
In , a method of selective anion exchange capacity
gradient chromatography with a borate eluent was
recommended. Another way to change the concentration
of functional groups is by addition of an ion pair reagent
to the eluent, which diminishes the “effective” charge in
the surface layer of the ion exchanger .
The relationship between solvation processes in the
mobile phase and the ion exchange separation selectivity
1 + k
, where τ'
is the reduced retention time of ions of ith and jth types, being
, base widths of chromatographic peaks;
k' = τ'
, retention factor; k
)/2; and N, number of