Aliquots of the solutions were selected and their pH and ionic
strength were adjusted at appropriate amount. A 50.0 mL of solutions
was placed in a 55.0 mL screw cap glass tube and spiked with
the metal ions at 20 ng L1 level and suitable amount of PAN was
added. The ions in the aqueous solution were complexed with
PAN. Suitable volume of acetone containing microliter volume of
1-undecanol was rapidly injected into the sample solution. A
cloudy solution was formed in the test tube. The mixtures were
centrifuged for 5 min at 4000 rpm. Accordingly, the dispersed fine
droplets of the extraction solvent was floated at the top of test
tube. The test tube was transferred into an ice bath and the organic
solvent was solidified after 5 min and then, the solidified solvent
was transferred into a conical vial where it was melted immediately
at room temperature. In order to decrease the viscosity of
organic phase, 150 lL ethanol was added. Finally, it was injected
into ICP-MS by a flow injection system.