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: Water -> fish farming

Citations 3

"Flow Injection Atomic Spectrometric Determination Of Inorganic Arsenic(III) And Arsenic(V) Species By Use Of An Aluminum-column Arsine Generator And Cold-trapping Arsine Collection"
Anal. Chim. Acta 1992 Volume 261, Issue 1-2 Pages 105-113
M. Burguera, J. L. Burguera and M. R. Brunetto, M. de la Guardia and A. Salvador

Abstract: The sample is injected into water as carrier and the solution (with or without introduction of 10% KI solution to reduce As(V)) is mixed with 5 M NaOH before passage through an electrically heated Pyrex column containing a rolled foil of metallic Al (~1 g) to reduce As(III) to AsH3. The AsH3 passes to a gas - liquid separator and is collected for 3 min in a liquid-N-cooled trap. The trap is then placed in hot water, and He is used to sweep the AsH3 into a fused-silica cell above an air - acetylene flame for AAS measurement at 193.7 nm. Analysis for As(III) and total As takes ~10 min. Optimized operating conditions are given. Interference in the determination of 1 ng of As(III) was caused by >10 ng of Ni, Be, Cr(III), Ag, Pb, Cu(II), Sn, Zr, or Fe(III). The detection limit was 0.25 µg L-1 of As(III) or As(V). The method was successfully applied to water samples from a trout fishery. A flow injection system is described for the selective determination of arsenic(III) and arsenic(V) (0.05-20 ng) in a 100 µL sample volume by hydride generation and atomic absorption spectrometry. An elec. heated aluminum column was used to generate the arsine in an alkaline medium. Recoveries averaged 97-99% for arsenic(III) and 95-98% for arsenic(V) with relative standard deviations of less than 4.3% in each instance. The detection limit was 0.25 µg L-1 (25 pg) of arsenic in both instances. This method was relatively free from interferences and was applied successfully to the determination of arsenic(III) and arsenic(V) in trout fishery water samples. The data obtained were compared with those produced by a hydride generation-cold trapping atomic absorption spectrometric detection method, using sodium tetrahydroborate(III) in hydrochloric acid. The results obtained by both methods were in close agreement, within 96-102%.
Arsenic(3+) Arsenic(5+) Arsenic, inorganic Spectrophotometry Spectrophotometry Interferences Method comparison Column Heated reaction Cold trap

"Sequential Automatic Online Determination Of Aquiculture Nutrients: Phosphate And Nitrate"
J. Autom. Methods Manag. Chem. 1992 Volume 14, Issue 5 Pages 173-175

Abstract: A method was devised for single-channel continuous-flow analysis of NO3- and PO43- in waters with use of a programmable switching valve. For PO43- the reagent was 5% molybdate - 2% ascorbic acid in 2 M HNO3 - glycerol (9:1) and for NO3- the reagent was 0.38% sulfanilamide - 0.144% N-1-naphthylethylenediamine in 4% HCl containing 1.6% NaCl. Rectilinear calibration ranges were 5 to 100 µg mL-1 for NO3- and 1 to 20 µg mL-1 for PO43- and operational ratios of NO3- to PO43- were 1:4 to 100:1 with sampling at up to 45 h-1. The method has been applied to fish-farm seawater.
Phosphate Nitrate Spectrophotometry Valve Automation

"Unsegmented Flow Approach For Online Monitoring Of PH, Conductivity, Dissolved Oxygen And Determination Of Nitrite And Ammonia In Aquaculture"
J. Autom. Methods Manag. Chem. 1994 Volume 16, Issue 2 Pages 59-62

Abstract: Two procedures based on continuous unsegmented techniques have been developed for online measurements of water samples. Monitoring, of pH, conductivity and dissolved oxygen content was achieved with serial detectors. Monitoring of nitrite and ammonia was based on the Greiss diazotization reaction and the Nessler reaction for ammonia with detection for both at 500 nm. Automatic control of a switching valve allowed the change of sample and reagent volumes and detector sensitivity. The photometric detector was independent of salinity allowing analyte to be determined in seawater. Consistent results were obtained between continuous and static measurements on seawater, and the procedures have been used to monitor these parameters in samples taken from a fish farm.
Nitrite Ammonia Conductometry Electrode