Determination of Gallium in Rare Earth Ore by Inductively Coupled Plasma-Mass Spectrometry Using Polyurethane Foam Pre-concentration/Separation

Gallium in rare earth ore is commonly determined by Inductively Coupled Plasma-Mass Spectrometry(ICP-MS), but high content of rare earth will result in significant mass spectrum interferences.In this study, Ga in sample solution was absorbed by polyurethane foam in 6 mol/L HCl.Gallium adsorbed on the foam could be quantitatively eluted with 0.5 mol/L NH₄Cl solution in a heating water bath for 30min.The adsorption-eluted efficiency is higher than 99%.Most of the matrix elements could be separated from Ga by polyurethane foam so the mass spectrum interferences were reduced effectively.The detection limit was 0.022μg/g.The accuracy of the developed method was evaluated by analyzing Ga in soil and stream sediment standard reference materials.The proposed method was successfully applied to gallium determination in geological samples and rare earth ores.The recoveries are 94.1%-100.6% and the precision is 2.2%-4%(RSD, n=12).