PRECONCENTRATION OF RARE-EARTH ELEMENTS IN SEAWATER WITH POLY(ACRYLAMINOPHOSPHONIC DITHIOCARBAMATE) CHELATING FIBER PRIOR TO DETERMINATION BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

A new ion-exchange chelating fiber with aminophosphonic and dithiocarb amate groups based on polyacrylonitrile was developed for the preconce ntration of rare earth elements (REEs) in seawater prior to their dete rmination by inductively coupled plasma mass spectrometry. REEs can be easily separated from the high-saline matrix using the fiber. The opt imum experimental parameters such as pH, now rate, sample volume, and effect of matrix ions for preconcentration of REEs were investigated. All REEs in water can be quantitatively retained in the acidity range of pH 3-6 by the fiber and then eluted quantitatively with 0.01 mol L- 1 ammonium citrate. The fiber has been applied to the concentration of REEs in seawater. The relative standard deviations for the determinat ion of REEs in seawater at nanogram per liter levels were found to be less than 5%. A reasonably good agreement is obtained with the data re ported in the literature.