title: Hollow fiber based liquid-phase microextraction for the determination of mercury traces in water samples by electrothermal atomic absorption spectrometry.
abstract: A three-phase liquid microextraction procedure for the determination of mercury at low concentrations is discussed. To the aqueous sample placed at pH 7 by means of a phosphate buffer, 0.002% (m/v) 1-(2-pyridylazo)-2-naphthol (PAN) is incorporated, and the mixture submitted to microextraction with a hollow-fiber impregnated with toluene and whose lumen contains a 0.05 mol L(-1) ammonium iodide solution. The final measurement of the extract is carried out by electrothermal atomic absorption spectrometry (300°C and 1100°C for the calcination and atomization temperatures, respectively). The pyrolytic graphite atomizer is coated electrolytically with palladium. An enrichment factor of 270, which results in a 0.06 μg L(-1) mercury for the detection limit is obtained. The relative standard deviation at the 1 μg L(-1) mercury level is 3.2% (n=5). The reliability of the procedure is verified by analyzing waters as well as six certified reference materials.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, Murcia, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: López-García
authors.forename: Ricardo E
authors.initials: RE
authors.lastname: Rivas
authors.forename: Manuel
authors.initials: M
authors.lastname: Hernández-Córdoba