University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

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Classification: Environmental -> air -> indoor

Citations 1

"Evaluation Of A Diffusive Sampling Method For The Determination Of Atmospheric Ammonia"
Fresenius J. Anal. Chem. 1995 Volume 351, Issue 1 Pages 19-26
Wolfgang Frenzel, Ewald Grimm and Gesa Gruetzmacher

Abstract: NH3 was collected in H3PO4 coated bottoms of glass phials followed by FIA. The samplers (3 at each site) were covered with a hydrophobic microporous membrane (PTFE tape) and hung upside down. After exposure, the tube-type samplers were opened under NH3-free air and 1 mL water was pipetted into each phial. After shaking, a 320 µL portion of the solution was pipetted into FIA system. Sample was mixed with a water carrier stream (1.4 ml/min) via an FIA manifold (schematic given) and 10 g/l NaCl in 1 M NaOH (0.4 ml/min) in a mixing coil. The resulting stream was mixed with an acceptor stream of 0.1 g/l bromocresol purple (0.6 ml/min) in a gas diffusion unit comprising channels (33 cm x 3 mm width x 0.1 mm depth). Detection was spectrophotometrically at 585 nm. The calibration range was linear from 0.5-100 µg/l (as NH3) and RSD were 1-3%. The standard deviation (n = 30) of the method was 0.33 ng and the sampling frequency was 20 samples/h. The detection limit under optimized conditions was 2.3 x 103:m3 s. The method was applied to outdoor and indoor measurements.
Ammonia Spectrophotometry Gas diffusion Optimization