Rare-earth elements in samples of geological interest are separated from other elements and concentrated onto ion exchange membrane through ion-exchange procedures.The membrane is then used to determine the REE by X-ray fluorescence spoctrography.In comparison with the traditional thick-sample approach, the weight of sample (REE.oxides) required in this method is reduced from 10 to 1 mg. Variable-internal standard method is adopted to determine the relative concentrations of REE in the membrane.Area density of the sample is controlled at about 0.0003 g/cm2 so that matrix effect can be eliminated to a satisfactory extent. Interference calibration between spectrolines and background determination are also improved, with the detection limit reaching 2.5×10-6g.
展开▼
