2,4,6-Trichlorophenol (2,4,6-TCP) was extracted from liquid samples (standards and spiked river water) using immuno-supported liquid membrane (ISLM) extraction followed by fluorescence flow immunoassay (FFIA) detection of the immuno-extracted analyte. ISLM-FFIA involves simultaneous on-line sample clean-up, enrichment and detection of analytes. The analyte is transported from a continuously flowing aqueous sample phase (donor) through a supported liquid membrane (SLM), containing an immobilised organic solvent, to a stagnant aqueous phase (acceptor), containing excess anti-analyte antibody, where it is trapped as analyte-anti body complex. The acceptor content is then dispensed and mixed on-line with a fluorescent analyte tracer (2,4,6-TCP/NH/(CH2)(3)/CO/EDF) and the resulting labelled fraction, separated from the mixture by restricted access column, is an indirect measure of the analyte amount extracted in the acceptor. The performance of ISLM-FFIA was compared with a similar FFIA (without the extraction step) with the following results: the ISLM-FFIA configuration leads to improved assay sensitivity (LOD 27.92 +/- 2.44 and 224 +/- 15.86 mu g L-1 for ISLM-FFIA and FFIA, respectively) and improved selectivity and recovery for 2,4,6-TCP in presence of other chlorophenols (e.g. 2,4,5-trichlorophenol and 4-chlorophenol) compared to FFIA alone. (c) 2005 Elsevier B.V. All rights reserved.