Coupling of biological sample handling and capillary electrophoresis

The analysis of biological samples (e.g., blood, urine, saliva, tissue homo genates) by capillary electrophoresis (CE) requires efficient sample prepar ation (i.e., concentration and clean-up) procedures to remove interfering s olutes (endogenous/ exogenous and/or low-/high-molecular-mass), (in)organic salts and particulate matter. The sample preparation modules can be couple d with CE either off-line (manual), at-line (robotic interface), on-line (c oupling via a transfer line) or in-line (complete integration between sampl e preparation and separation system). Sample preparation systems reported i n the literature are based on chromatographic, electrophoretic or membrane- based procedures. The combination of automated sample preparation and CE is especially useful if complex samples have to be analyzed and helps to impr ove both selectivity and sensitivity. In this review, the different modes o f solid-phase (micro-) extraction will be discussed and an overview of the potential of chromatographic, electrophoretic (e.g., isotachophoresis, samp le stacking) and membrane-based procedures will be given. (C) 1999 Elsevier Science B.V. All rights reserved.