a separation column so that the separation device 14 is purged by the carrier gas 16 in the second valve position shown here as a dashed line the combustion products 9 coming from the burner 5 are guided directly to the gas outlet 12 the dosing volume 11 is then switched into the gas path between the carrier gas source 13 and the separation device 14 so that the carrier gas 16 pushes the combustion products 9 contained in the dosing volume 11 as a plug of gas through the separation device 14 in this process the sulfur dioxide is separated from the other combustion products and then quantitatively determined in a detector 17 in the embodiment shown the detector 17 is a flame photo detector fpd however other detectors suitable for detecting sulfur dioxide e g a thermal conductivity detector tcd may also be used all the parts of the depicted arrangement that carry the combustion products 9 are kept within a temperature range greater than 100 u00b0 c to prevent condensation of water vapor which is one of the combustion products and to prevent the formation of acids the area of the feed path 18 for the sample 1 between the sample vaporizer 4 and the burner.