Chemistry Reference
In-Depth Information
Flow injection analysers available range from relatively low-cost unsophisticated
instruments such as those supplied by Advanced Medical Supplies, Skalar and ChemLab
to the very sophisticated instruments such as the FIA star 5010 and 5020 supplied by
Tecator (Table 1.2).
1.1.4
Segmented flow analysis
This is a variant on flow injection analysis in which instead of injecting sample into a
carrier reagent stream the reagents are injected into a sample stream. Some applications
are listed below,
Non saline waters:
bicarbonate, carbonate, nitrite and nitrate.
Seawater:
bromide.
Surface and
ground waters:
bromide.
Continuous flow analysis
Non saline waters:
nitrate, nitrite and sulphite.
Sea water:
nitrate and nitrite.
Aqueous precipitation:
bromide, chloride, nitrate, nitrite, phosphate, sulphate and thiocyanate.
Potable water:
nitrate and sulphate.
Trade effluents:
free cyanide.
1.1.5
Spectrometric methods
1.1.5.1
Atomic absorption spectrometric methods
Basically, the atomic absorption method was designed for the determination of cations.
However, it has been applied to the indirect determination of some anions. If, for
example, an excess of barium chloride solution is added to a sample containing sulphate
and the precipitated barium sulphate filtered or centrifuged off then determination of
excess barium ions by atomic absorption spectrometry enables the concentration of
sulphate ions in the sample can be calculated indirectly.
Some 18 anions have been indirectly determined in water samples by this method.
Non saline
waters:
arsenate, arsenite, borate, chloride, chromate, dichromate, free cyanide, total
cyanide, molybdate,
nitrate, phosphate, selenate, selenite, silicate and tungstate.
Seawater:
chromate, dichromate, selenate and selenite.
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