Simultaneous determination of inorganic and organic acids in air by use of annular denuders and ion chromatography

The performance of KOH-coated annular denuders for simultaneous collection of gas-phase atmospheric organic and inorganic acids has been evaluated by ion chromatography (IC) with an NaOH−H2O gradient. Sampling efficiency was tested for formic and acetic acids under dry and humid air conditions. With this method several mono- and dicarboxylic acids, nitric acid, and hydrogen chloride can be detected. Laboratory and field measurements confirmed the reliability of the denuder method and its superior versatility compared with other techniques (scrubbing by means of a nebulizer, cryogenic trapping) which cannot be used to determine termine gaseous inorganic acids.