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  • Author or Editor: G. Wals x
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Abstract  

The combination of wet open mineralization with a saturated Mg(NO3)2-solution and the scavening of trace elements by active carbon are discussed. Experiments with spiked aliquuots serve to establish the chemical yeilds. The procedure is then checked by the analysis of Standard (Reference) Materials from the NBS and the IAEA. The elements Sc, Fe, Co, Zn, Cu, Se, Sb, W, Hg, Au and some lanthanides can be obtained with no apparent systematic bias and at a reasonable precision.

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Abstract  

A neutron activation analysis method for the determination of Se(IV) in natural waters is described. It is based on the coprecipitation of the metal dibenzyldithiocarbamate with phenolphthalein. The precipitate is collected on 0.45 m membrane filters and selenium is determined by instrumental neutron activation. A Se(IV) radiotracer (75Se, T=120 d) was used to establish optimum conditions and to evaluate the chemical yield. Samples of sea and canal water were analyzed.

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Abstract  

The determination of fluoride in aqueous solutions by substoichiometric extraction was performed using a carrier-free spike of18F (T=110 m). The principle, the procedure of the determination and the results of some tap water and urine analysis are given.

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Abstract  

A simple method is presented for the determination of inorganic arsenic in water samples. The lower limit of determination is 0.01 μg·1−1. Penta-and trivalent arsenic ions as well as arsenic acid substituted with aromatic ligands are collected by coprecipitation with Fe(OH)3. After irradiation the arsenic is separated from the iron by adsorption to Al2O3. The overall efficiency is (97∓1)%. The procedure takes one day per ∼20 samples. It has been checked by standard addition. Data for sea- and surface-water are given. As the concentration of aromatic arsenic-compounds is very small in comparison to that of the inorganic species, it does not affect the result of the determination.

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Abstract  

The interferences by uranium fission on the determination by neutron activation analysis of Zr, Mo, Ru, La, Ce, Nd and Sm are investigated for the Argonaut-type Low Flux Reactor at ECN, Petten, The Netherlands. In addition, the spectral interference of the determination of Sm by239Np is considered. The experimental values for fission yields are found to be in good agreement with calculated values based on recent cross-section compilations.

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