1. Introduction However, for some sample categories the obtained
resolution is not satisfying. Even if the resolution is
Ion chromatography has become a powerful, wide- sufficient, the separation can be optimized in order to
ly used analytical method enabling simple, selective shorten the run time. An example is the separation of
and fast determination of a variety of inorganic and multivalent metal cations on strong cation-exorganic
anions and cations [1–4]. changers [1–4]. The well performing silica gel type
In the present sense it comprises a combination of exchangers are not suitable for acidic or alkaline
classical ion-exchange techniques with modern in- samples because of either loss of functional groups at
strumentation and high-performing stationary phases. low pH or complete dissolution at high pH [1–4].
Those separations are important in the field of ultra
*Corresponding author. Tel.: 149-6421-2825-661; fax: 149- trace analysis with sophisticated techniques such as
6421-2822-124. online coupling IC–ICP-(AES, MS) [5].
E-mail address: seubert@mailer.uni-marburg.de (A. Seubert). One possible way to optimize ion chromatographic
0021-9673/02/$ – see front matter Ó 2002 Elsevier Science B.V. All rights reserved.
PII: S0021-9673(01)01538-2