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Evaluation of a fluorometric method for measuring low concentrations of ammonia in ambient air.

Authors
Groves-WA; Agarwal-D; Chandra-MJ; Reynolds-SJ
Source
J Environ Monit 2005 Feb; 7(2):163-168
NIOSHTIC No.
20028822
Abstract
A fluorometric method developed for measuring low concentrations of ammonium in marine and freshwater ecosystems was adapted for the analysis of ammonia in ambient air. The modified method entails collection of samples on an acid-treated solid adsorbent followed by analysis using a fluorometer. Optimal results were obtained using a commercially available sorbent tube containing 100 mg of acid-treated silica gel for sample collection, and an analytical protocol consisting of sample desorption in DI water, addition of orthopthaldialdehyde (OPA) working reagent, and room temperature incubation. Method accuracy and precision were evaluated by comparing experimentally determined quantities of ammonia to expected levels for sample loadings ranging from 0.16 [micro sign]g to 550 [micro sign]g-accuracy was generally within +/-20%. The estimated LOQ for the method is 0.08 [micro sign]g ammonia per sample which represents a 25-375-fold improvement in sensitivity compared to current NIOSH and OSHA methods for the measurement of ammonia in ambient air. The new method should be useful for applications requiring measurement of low concentrations of ammonia using personal sampling equipment or in the characterization of short-term fluctuations of ammonia concentrations in air.
Keywords
Airborne-particles; Ammonium-compounds; Air-samples; Air-sampling; Fluorometry; Air-sampling-equipment; Sampling-equipment; Sampling; Sampling-methods
CODEN
JEMOFW
CAS No.
7664-41-7
Publication Date
20050201
Document Type
Journal Article
Funding Amount
108000
Funding Type
Grant
Fiscal Year
2005
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-K01-OH-000177
Issue of Publication
2
ISSN
1464-0325
Source Name
Journal of Environmental Monitoring
State
PA
Performing Organization
Penn State University, University Park, Pennsylvania
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