Microwave assisted UV-digestion

Full text: A novel, microwave assisted, high temperature UV-digestion for accelerated decomposition of dissolved organic compounds or slurries was developed. UV irradiation is generated by immersed electrodeless Cd discharge lamps (228 nm) operated by the microwave field in the oven cavity. The high pressure - high temperature digestion vessels of the new MULTIWAVE 3000 offer ideal conditions for this decomposition technique at temperature up to 250 - 280 oC. Compared to open UV digestion devices, decomposition time is reduced by a factor of five. Up to 0.1 g powdered organic material are digested with just 1 ml H2O2, 5 ml H2O and 0.1 ml HNO3. The remaining organic carbon content is about 5-10 %. With the unique design of the new MULTIWAVE 3000 the digestion vessels can be additionally loaded with oxygen. The digestion efficiency is improved significantly and the residual organic carbon drops down to 1-2 %. This new technique is ideal for extreme trace analysis due to the low blank values and low acid concentration. In addition this digestion method can be used for the determination of nonmetals like halogens by ion chromatography. (author)