Wet effluent parallel plate diffusion denuder coupled capillary ion chromatograph for the determination of atmospheric trace gases.

We describe an inexpensive, compact parallel plate diffusion denuder coupled capillary IC system for the determination of soluble ionogenic atmospheric trace gases. The active sampling area (0.6x10 cm) of the denuder is formed in a novel manner by thermally bonding silica gel particles to the surface of Plexiglas plates. The effluent liquid from the parallel plate diffusion denuder is collected and preconcentrated on a capillary preconcentrator column before analysis using a capillary ion chromatograph. Using SO(2) as the test gas, collection efficiency is essentially quantitative at air sampling rates up to 500 ml min(-1). The system provides a limit of detection (LOD) of 1.6 parts per trillion for SO(2) for a 10 min sampling period.