Simultaneous ion-pair solvent-extraction preconcentration of 12 elements in natural water samples for the determination by inductively coupled plasma atomic emission spectrometry

Simultaneous preconcentration extraction by trioctylmethylammonium chloride (TOMA.Cl) for the determination of trace amounts of twelve elements (Bi(III), Cd(II), Co(II), Cu(II), Fe(II), Hg(II), Mo(VI), Pb(II), Sb(III), Sn(II), V(V), Zn(II)) in natural water samples is described. A water sample containing 0.3 mol dm(-3) HCl, 0.1 mol dm(-3) KI, 0.1 mol dm(-3) KSCN, and 0.01 mol dm(-3) ascorbic acid was shaken with 2%(w/v) TOMA.Cl in xylene with a volume ratio (V-aq/V-org) of 100. After preconcentration extraction, the organic phase was directly introduced into inductively coupled plasma atomic emission spectrometry. Twelve elements could be determined at the mu g dm(-3) or ng dm(-3) level. Some natural water samples as well as standard reference material were analyzed by the proposed method. The results were highly satisfactory.