A multiple parallel plate wetted screen diffusion denuder for high-flow air sampling applications

Diffusion denuders are commonly used today for air sampling applications where it is necessary to discriminate between gaseous-and aerosol-phase analytes. in some applications, such as isotopic analysis, it is necessarq'to collect a sufficient analyte mass necessitating high sampling rates. Wetted denuders are preferred in many applications because they can be readily coupled to automated continuous analysis systems. We describe here a-compact (5 cm diameter, 30 cm length) diffusion denuder with 11 individually wetted parallel screens (with an wetted area in excess of 0.1 m(2)) that allow operation at high now rates. The effluent liquid is collected at the bottom from two V-shaped grooves. With SO2 as the test gas, similar to 95% is collected even at a now rate of 50 L/min with very low particle losses.