Chemistry Reference
In-Depth Information
spectrophotometry after conversion to nitrogen monoxide. Detection limits are 5×10
−6
M
for nitrate and 1×10
−6
M for nitrite.
Nygaard [572] has described a pneumatoamperometric technique for the determination
of nitrite and nitrate. These ions are reduced to nitric oxide with hydroquinone then nitric
oxide purged from the sample and oxidised at a membrane covered anodically polarised
platinum electrode.
Martiadou-Nikolopoulou and Kouimtzis [587] studied the effects of
N-
cetylpyridinium
chloride, dodecylhydrogen sulphate sodium salt, dodecylbenzene sulphonate and Triton-
X-100 on the spectrophotometric determination of nitrite and nitrate in aqueous samples.
Two methods were used for nitrate determination, one based on the nitration of salicyclic
acid (higher nitrate levels) and one based on nitrate reduction to nitrite (low nitrate levels)
followed by nitrite determination. Cationic and non-ionic surfactants did not interfere
with nitrite determination whereas anionic surfactants caused significant interferences
which could be eliminated by treating the water with
n
-cetylpyridiniumbromide.
A study has been carried out of the accuracy of determination of total oxidised nitrogen
(nitrite plus nitrate and nitrite in river waters [413].
Various workers have reviewed methods for the determination of total nitrogen in non
saline waters [588-590].
2.65
Nitriloacetate
2.65.1
Polarography
Nitrolacetic acid has been preconcentrated from water at pH 3 by passage through an
anion exchange column and subsequent elution with sodium chloride [591] prior to
estimation by polarography.
2.65.2
Ultraviolet spectroscopy
Longbottom [592] preconcentrated nitrolacetic acid on a strong anion exchange resin,
then desorbed it with sodium tetraborate at pH 9 prior to estimation by ultraviolet
spectroscopy.
2.66
Octanedioate
2.66.1
Gas chromatography
The application of this technique is discussed under multianion analysis in section
14.1.1.1.
Search WWH ::
Custom Search