DEVELOPMENT AND LABORATORY INVESTIGATION OF A DENUDER SAMPLING SYSTEMFOR THE DETERMINATION OF CARBONYL-COMPOUNDS IN STACK GAS

A method for sampling and detection of low volatile carbonyl concentra tions (aldehydes and ketones) in stack gas is proposed. For this purpo se, a novel fourfold glass annular-denuder, coated with acidified 2,4- dinitrophenylhydrazine (DNPH) has been developed for the sampling of c arbonyl compounds under high temperature and high humidity emission co nditions. After sampling, the hydrazones are eluted with acetonitrile and analyzed using RP-HPLC. They are detected by UV-absorbance, with m aximum sensitivity obtained between 350 and 380 nm. The sampling effic iency has been investigated for different flow rates, temperatures and relative humidities. The influence of other trace gases (ozone, nitro gen dioxide) on the sampling system was investigated as well.