S26 Nitrogen Trichloride Detection in Indoor Pool Air using Proton Transfer Reaction Mass Spectrometry

Sunday, 6 January 2019
Hall 4 (Phoenix Convention Center - West and North Buildings)
Anna Feerick, University of Maryland Baltimore County, Baldwin, MD; and Y. Huangfu and B. T. Jobson

The purpose of this study is to accurately identify the concentration of nitrogen trichloride (NCl3) in indoor swimming pool environments using Proton Transfer Reaction Mass Spectrometry (PTR-MS). NCl3, a chloramine compound that forms from the reaction of HOCl and NH3. It is a disinfection by-product that has been correlated to increased cases of asthma in swimmers. The amount of NCl3 produced is dependent on the number of swimmers, the amount of NH3 / urea released, the air change rate of the building, the amount of sunlight, and the concentration of HOCl in the water. In this work known concentrations of NH2Cl, NHCl2, and NCl3 were synthesized and stock solutions quantified by UV/VIS spectrometry. Stock solutions were then used to make test gas mixtures for determining the PTR-MS response factors for these compounds. Test gas mixtures were made by calculating gas phase concentrations from stock solution concentrations and the Henry’s Law coefficient of the chloramines. Preliminary results have confirmed the PTR-MS’s ability to measure NCl3. The continuous PTR-MS measurement method would thus be valuable for better determining exposures of NCl3 by swimmers and pool workers. Further research will include testing the PTR-MS in an indoor pool environment and determining the NCl3 concentration in the air.
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