Developments in hollow fibre-based, liquid-phase microextraction

The demand for automation in analytical liquid-liquid extraction (LLE) combined with organic solvent reduction or elimination has led to the recent development of liquid-phase microextraction (LPME) based on disposable hollow fibres. In this concept, analytes of interest are extracted from aqueous samples, through a thin layer of organic solvent immobilized within the pores of a porous hollow fibre, and into an acceptor solution inside the lumen of the hollow fibre. Subsequently, the acceptor solution is directly subjected to a final analysis by capillary gas chromatography (CGC), high-performance liquid chromatography (HPLC), capillary electrophoresis (CE), or mass spectrometry (MS) without any further effort. Hollow fibre-based LPME may provide high analyte pre-concentration and excellent sample clean-up, and it has a broad application potential within areas such as drug analysis and environmental monitoring. This review focuses on basic extraction principles, technical set-up, recovery, enrichment, extraction speed, selectivity, applications, and future trends in hollow fibre-based LPME. (C) 2003 Elsevier Ltd. All rights reserved.