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
Email: schalk@unf.edu
Website: @unf

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Cloud

Classification: Environmental -> water -> cloud

Citations 3

"Determination Of Ammonium In Aerosols, Cloud And Rain Water, And Of Gaseous Ammonia In The Troposphere"
Fresenius J. Anal. Chem. 1987 Volume 327, Issue 1 Pages 16-16
U. Sprenger and K. Bächmann

Abstract: Four methods were compared for the determination of NH4+. An UV - visible spectrophotometric determination is described which involved treatment of NH4+ with an alkaline solution of 4,4'-bis-(3-methyl-1-phenylpyrazolin-5-one) in the presence of chloramine T at pH 6, extraction with trichloroethylene after acidification, and measurement of the absorbance at 455 nm. Two flow injection analysis methods are described involving injection of a sample into a stream of NaOH to produce NH3 which diffuses across a permeable membrane into a flowing acceptor stream. In the first method, the acceptor is bromothymol blue solution and the absorbance is measured at 620 nm, and in the second, the acceptor is water and the change in conductivity is measured. The last method described involves ion chromatography and conductivity detection. The sample volume, detection limits, reproducibilities and analysis times are given for the four methods. A possibility for sampling gaseous NH3 is by formation of ammonium oxalate on cellulose filters coated with oxalic acid.
Ammonium Spectrophotometry Cellulose Gas diffusion Membrane Method comparison

"FIA Of Fog- And Rain-water Acidity"
Bunseki Kagaku 1993 Volume 42, Issue 10 Pages 631-633
Suzaki, H.;Okochi, H.;Igawa, M.

Abstract: The acidities of samples at pH 4.8 and 8.3 were determined by FIA using carbonate-free 1 mM NaOH as carrier solution and Bromothymol blue and Bromophenol blue, respectively, as indicators. The half-width of the signal peak was used for the calibration. The results obtained using FIA generally agreed well with those obtained by a titration method. The pH 8.3 acidity determined by FIA and the total acidity determined by titration were always greater than the H+ concentration due to the presence of NH4+ and organic acids.
Acidity Spectrophotometry Method comparison

"Analysis Of Aldehydes In Cloud- And Fog-water Samples By HPLC With A Post-column Reaction Detector"
Environ. Sci. Technol. 1989 Volume 23, Issue 5 Pages 556-561
Manabu Igawa, J. William Munger, and Michael R. Hoffmann

Abstract: Samples were collected as described previously (Jacob et al., Anal. Abstr., 1986, 48, 5H1), and were analyzed on a column (25 cm x 4.6 mm) of Spherisorb ODS-2 (5 µm), operated at 30°C, with a guard column of Adsorbosphere C18, aqueous 40 or 1% acetonitrile as mobile phase (0.5 mL min-1), and post-column reaction with 3-methylbenzothiazolin-2-one hydrazone (details given) before detection at 640 nm. Detection limits were 42 nM to 9 µM for 100 µL injections. Calibration graphs of peak height vs. concentration were rectilinear. Results showed good agreement with those obtained by using 2,4-dinitrophenylhydrazine, but the cited method was less cumbersome and less time consuming.
Aldehydes HPLC Spectrophotometry Post-column derivatization