INVESTIGATION OF SAMPLE DECOMPOSITION FOR THE TRACE DETERMINATION OF ARSENIC, ANTIMONY AND SELENIUM IN ORGANIC AND INORGANIC MATERIALS USING THE WICKBOLD COMBUSTION METHOD

The suitability and efficiency of the Wickbold combustion unit in comb ination with the new pre-combustion unit VE (manufactured by Fa. Herae us Quarzglas GmbH) is investigated with respect to its use for the dec omposition of samples for the determination of the trace elements arse nic, antimony and selenium. Certified solid reference samples were ana lyzed for their contents of these elements by decomposition in this ap paratus and detection by hydride-AAS. Several additional experimental parameters were investigated in detail. Different absorption solutions were tested as well as the influence of the temperature of the new ov en and the influence of the sample size. The new pyrolysis unit is com pared with the traditional Wickbold pyrolysis method. Furthermore, the Wickbold method and an aqua regia extraction were compared. The advan tages of the Wickbold unit combined with the new combustion unit are s hown (especially) for routine analysis of several volatile elements. T he versatility of the unit for this group of elements is demonstrated for inorganic as well as organic samples. As there is tittle need for additional chemicals, this method works with almost no blank value, re sulting in very low limits of detection. These are mainly influenced b y the method of detection. It is possible to detect 2 mug/L arsenic, 3 mug/L selenium and 5 mug/L antimony without enrichment.