Page 256 - Multidimensional Chromatography

Multidimensional Chromatography
Edited by Luigi Mondello, Alastair C. Lewis and Keith D. Bartle
Copyright © 2002 John Wiley & Sons Ltd
ISBNs: 0-471-98869-3 (Hardback); 0-470-84577-5 (Electronic)

11 Multidimensional Chromatography:
Biomedical and Pharmaceutical

Applications

G.W. SOMSEN and G.J. de JONG
University of Groningen, Groningen, The Netherlands

11.1 INTRODUCTION

Today, separations play a central role in the analysis of pharmaceutical and biologi-
cal samples. Because many samples are very complex and the concentration levels of
interest decrease, systems with high efficiency and selectivity are needed. Another
strong requirement is the reduction of analysis time, because the number of samples
continues to increase and information has to become available rapidly. This also
means that attention is needed for sample pretreatment procedures which preferably
have to be integrated with the analysis step, if possible in an automated fashion. The
coupling of chromatographic systems in the same mode or even the combination of
different chromatographic modes has shown a high potential in order to reach these
goals. These so-called multidimensional chromatography systems offer many possi-
bilities to increase the selectivity, and thus the sensitivity of the total analytical
system, especially when more or less orthogonal techniques are combined.
This present chapter describes the application of multidimensional chromatogra-
phy (including capillary electrophoresis) in the biomedical and pharmaceutical field.
Because liquid chromatography (LC) is the main technique in these areas, LC is
often at least one of the components of such a coupled-column system. The coupling
of two LC columns is now routine and widely used, and at present LC coupled to gas
chromatography (GC) is applied for bioanalysis as well. The on-line coupling of
solid-phase (micro)extraction (SPE and SPME) with LC or GC for the determination
of substances of biological and/or pharmaceutical interest will also be discussed. In
this respect, special attention will be paid to the use of selective sorbents in on-line
SPE. The biomedical application of supercritical fluid extraction (SFE) in coupled
chromatographic systems will also be treated briefly. Finally, applications of multidi-
mensional systems involving capillary electrophoresis (CE), which has a high poten-
tial for the separation of drugs, peptides and proteins, will be described. The goal of
this chapter is not to present an overview of all relevant applications, but rather to
stress the potential of the various multidimensional systems in the biomedical and