Hollow fiber based liquid-phase microextraction for the determination of mercury traces in water samples by electrothermal atomic absorption spectrometry

► Hg (II) traces are preconcentrated by means of a three-phase liquid microextraction system. ► PAN and ammonium iodide are used in the donor and acceptor phase, respectively. ► Hollow-fiber pores are continuously fed with toluene placed in the lumen. ► Mercuric ions can be measured in waters below the μg L−1 level.