PASSIVE DOSIMETER FOR MONITORING AMMONIA VAPOR

A method is presented for ammonia detection in the vapor phase that exploits the reaction between fluorescamine and ammonia on a sodium lauryl sulfate (NaLS)-treated paper substrate. The fluorescence intensity of the aquamarine fluorescence product is used as a measure of the air vapor concentration (AVC) of ammonia. The substrate treatment with NaLS enhances the intensity of the fluorescent product and improves the reproductibility of the determination of ammonia. The paper substrate is mounted on a dosimeter and used to monitor exposure to ammonia vapor. The developed dosimeter is a self-contained, badge-sized device that passively collects ammonia on a precoated filter-paper at a rate determined by molecular diffusion. The dosimeter can detect ammonia AVC at the ppm level after only 1 min of exposure. For an 8-h exposure period the limit of detection is ca. 1 ppb.