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-r...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/cm^2 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.展开更多
This work is intended to explore a fast and effective apoproach to the determination of various trace elements in geological samples throuth improvement and simplification of the method developed by Reynolds (1963,196...This work is intended to explore a fast and effective apoproach to the determination of various trace elements in geological samples throuth improvement and simplification of the method developed by Reynolds (1963,1967),Absorption correction was made for the Fe content to eliminate the effect caused by inconsistency in mass absorption coefficients among the samples.A computer-aid regression analysis was performed on a number of standards of various compositions,which resulted in a set of calibration equations for directly converting X-ray intensities to concentrations.An analytical error of 10-30% was involved in the analyses of most elements.展开更多
文摘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/cm^2 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.
文摘This work is intended to explore a fast and effective apoproach to the determination of various trace elements in geological samples throuth improvement and simplification of the method developed by Reynolds (1963,1967),Absorption correction was made for the Fe content to eliminate the effect caused by inconsistency in mass absorption coefficients among the samples.A computer-aid regression analysis was performed on a number of standards of various compositions,which resulted in a set of calibration equations for directly converting X-ray intensities to concentrations.An analytical error of 10-30% was involved in the analyses of most elements.
