Selenium in environmental waters: Determination, speciation and concentration levels.

Preconcentration methods for the analysis of water by x-ray spectrometric techniques

Selenium in human urine determination, speciation and concentration levels.

Chelex-100 ion-exchange filter membranes for preconcentration in x-ray-fluorescence analysis of water

The results of an investigation, the purpose of which was to study the feasibility of analysis of La, Ce, Pr, and Nd in apatite minerals, utilizing x-ray fluorescence spectrometry (XRF), are discussed. After sample dissolution in HNO/sub 3/, rare-earth elements (REEs) are separated by a mixed solvent anion exchange using the batch extraction technique. The anion exchanger employed is the strongly basic resin Dowex 1X8, 100 to 200 mesh (nitrate form). REEs are fixed on the resin from a medium consisting of 95% CH/sub 3/OH-5% 7 M HNO/sub 3/ (v/v). The dried resin is uniformly spread over a disk of self-adhesive foil backed with a cellulose support. The thin resin film formed is then used for XRF analysis. Synthetic standards prepared following the same procedure are employed for calibration. Analytical results of two apatite samples are presented. Good correlation is obtained between XRF and neutron activation analysis data. Limits of detection, precision, and accuracy of the results are discussed.

Determination of light rare earth elements in apatite by x-ray fluorescence spectrometry after anion exchange extraction

Enrichment Procedures for Water Analysis by X-Ray Energy Spectrometry

The capability of energy-dispersive X-ray fluorescence was investigated for fast and simple chemical analysis of trace elements in sediments and particulate matter in sea water. Nuclepore 0.4 μm pore-size membranes are recommended as optimal filters for a straightforward collection of suspended material. The collection of suspended trace metals by filtration seemed to give a sufficiently homogeneous filter load (s% <2.5). Data are presented on the concentrations of K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Pb, Rb and Sr with a fair precision (s% < 5.6) and accuracy.

M. Vanderstappen

Papers

Enrichment Procedures for Water Analysis by X-Ray Energy Spectrometry

Trace metal analysis of sediments and particulate matter in sea water by energy-dispersive X-ray fluorescence