scholarly journals Unsegmented flow approach for on-line monitoring of pH, conductivity, dissolved oxygen and determination of nitrite and ammonia in aquaculture

1994 ◽  
Vol 16 (2) ◽  
pp. 59-62 ◽  
Author(s):  
A. C. Ariza ◽  
P. Linares ◽  
M. D. Luque de Castro ◽  
M. Valcárcel
Keyword(s):  
Dissolved Oxygen ◽  
Continuous Monitoring ◽  
Sea Water ◽  
Flow System ◽  
Photometric Determination ◽  
Fish Feed ◽  
Fish Breeding ◽  
On Line ◽  
High Concentrations

A fully automated flow system for on-line monitoring of analytes/parameters of interest in aquaculture is described. The approach has been optimized for the photometric determination of nitrite and ammonia and the continuous monitoring of pH, conductivity and dissolved oxygen, but these analytes/parameters are readily changeable as required. The system has been tested by monitoring these species in the input and output sea water streams of tanks at a fish breeding farm and also by monitoring water containing high concentrations of fish feed.

Photometric determination of silicate in sea water

1936 ◽  
Vol 8 (6) ◽  
pp. 455-457 ◽  
Author(s):  
Rex J. Robinson ◽  
Herbert J. Spoor
Keyword(s):  
Sea Water ◽  
Photometric Determination

scholarly journals Photometric Determination of Mercury in Sea Water

1961 ◽  
Vol 82 (3) ◽  
pp. 347-349 ◽  
Author(s):  
Hiroshi Hamaguchi ◽  
Rokuro Kuroda ◽  
Kyouichi Hosobara
Keyword(s):  
Sea Water ◽  
Photometric Determination

On-Line Trace Enrichment and Determination of Uranium in Waters by Flow Injection Inductively Coupled Plasma Mass Spectrometry

1994 ◽  
Vol 48 (11) ◽  
pp. 1331-1336 ◽  
Author(s):  
Shayessteh Dadfarnia ◽  
Cameron W. McLeod
Keyword(s):  
Mass Spectrometry ◽  
Flow Injection ◽  
Inductively Coupled Plasma ◽  
Sea Water ◽  
Trace Enrichment ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
On Line ◽  
Line Trace

A flow injection system incorporating a microcolumn of activated alumina was combined with inductively coupled plasma mass spectrometry for on-line trace enrichment and determination of uranium in surface waters and sea water. Deposition of uranium was effected with the use of a basic alumina microcolumn, and injection of nitric acid (250 μL, 2M) served to elute retained species to the ICP. A sample volume of 14 mL resulted in a preconcentration factor of 40, and precision at the 50-ng 1−1 level was 4.5% (RSD). The procedure was applied to mineral waters, river water, and sea water, and accuracy was assessed through either analysis of certified reference waters or recovery experiments.

Notes on the determination of dissolved oxygen in sea water

1939 ◽  
Vol 2 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Thomas G. Thompson ◽  
Rex J. Robinson
Keyword(s):  
Dissolved Oxygen ◽  
Sea Water

Determination of nitrate in sea water by cadmium-copper reduction to nitrite

1967 ◽  
Vol 47 (1) ◽  
pp. 23-31 ◽  
Author(s):  
E. D. Wood ◽  
F. A. J. Armstrong ◽  
F. A. Richards
Keyword(s):  
Standard Deviation ◽  
Sulphuric Acid ◽  
Sea Water ◽  
Colorimetric Method ◽  
Zinc Powder ◽  
Small Samples ◽  
Nitrosyl Chloride ◽  
Sensitivity Limit ◽  
High Concentrations

An accurate, dependable determination of 0–60 μg-at./l. of NO−3-N in sea water has been developed. The sample is treated with tetrasodium ethylenediaminetetraacetate solution and passed through a column of copperized cadmium filings. A nearly quantitative reduction of nitrate to nitrite results. Nitrite is then determined by a diazotization method. Neither sulphide nor high nitrite concentrations interferes. Approximately eight samples per hour per column can be analysed with a standard deviation of 0.12 μg-at./l. at the 20 μg-at./l. level.IntroductionAccurate determinations of nitrate ions in sea water have been difficult, especially under shipboard conditions.The colorimetric method described by Harvey (1926, 1930) and improved by Cooper (1932), Zwicker & Robinson (1944), and others uses strychnidine in concentrated sulphuric acid to produce a red colour. The reagent lacks reliable sensitivity, because it is dependent on the rates of mixing and cooling.In a method by Armstrong (1963), the absorbance of nitrosyl chloride in the UV region is measured with a spectrophotometer. While the method is good for small samples containing high concentrations of nitrate, the use of concentrated sulphuric acid and lack of sensitivity limit its use in routine analysis.A method in which nitrate is quantitatively reduced to nitrite would be advantageous, because nitrite can be readily determined by the sensitive diazotization method proposed by Griess (1879). Several such methods have been proposed. FØyn (1951), Vatova (1956), and Chow & Johnstone (1962) used zinc powder for the reduction, but the reduction is sensitive to temperature, and it is necessary to centrifuge or filter each sample.

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