Column solid-phase extraction using dithiocarbamate loaded polyurethane foam was applied to the preconcentration of trace amounts of As, Bi, Hg, Sb, Se and Sn from water samples prior to their measurement by simultaneous ICP-AES and ETAAS. The sorption recoveries of all the analytes were higher than 97% for 150 ml water sample solutions passed through the column with pH ≈ 4.5 and sodium chloride concentration up to 3%. For As, Bi, Hg, Sb and Se, quantitative solid-phase extraction can be achieved over a wide pH range, from 0.5 to pH 5. The combination of the proposed preconcentration method with subsequent simultaneous analyte determination in the methanol eluates by ICP-AES permits the detection of 3 mg l 21 As and Se, 8 mg l 21 Bi, 0.12 mg l 21 Hg, 2 mg l 21 Sb and 6 mg l 21 Sn in water samples. ETAAS measurement after dissolution of the sorbed analytes in isobutyl methyl ketone allows the detection of 0.06 mg l 21 As and Sb, 0.1 mg l 21 Bi and Sn, 0.08 mg l 21 Se and 0.3 mg l 21 Hg.

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A fusion method for the preparation of refractory powders for X-ray fluorescence (XRF) spectrometry, consisting of nickel based alloys is presented. The optimum conditions for the successful production of homogeneous stable glass discs by fusion were established. The sample preparation procedure was developed on the basis of a dilithium tetraborate flux with the addition of lithium carbonate and potassium-sodium carbonate in appropriate proportions and sodium nitrate as an oxidizing agent.The major elements Fe, Cr, Si and Ni were determined by comparison with synthetic calibration standards following the same procedure as for the test samples. The accuracy of the XRF analysis was checked by inductively coupled plasma atomic emission spectrometry and no statistically significant difference between the standard deviations of the two methods was found.

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