Chemistry Reference
In-Depth Information
7.2
Arsenate
7.2.1
Ion chromatography
The application of this technique is discussed under multianion analysis in sections 12.2.2
and 12.6.6.
7.3
Arsenite
7.3.1
Ion chromatography
The application of this technique is discussed under multianion analysis in sections 7.28.2
and 12.2.2.
7.4
Bicarbonate
7.4.1
Gas permeable membrane
Symanski and Bruckenstein [5,6] have described a simple method for the determination
of bicarbonate/carbon dioxide based on a conductionmetric sensor with a gas permeable
membrane. Although this method is very sensitive to bicarbonate/carbon dioxide, the
detector response to concentration is not linear. Also, acidic or basic gases such as
sulphur dioxide or ammonia interferes in the carbon dioxide determination.
7.4.2
Ion chromatography
This technique has been applied to the co-determination of carbonate and bicarbonate in
natural and potable waters [7].
7.4.3
Ion exclusion chromatography
Tanaka and Fritz [8] have described a procedure for the determination of bicarbonate and
carbon dioxide in water by ion exclusion chromatography using water as the eluent and
an electrical conductivity detector. The sensitivity of detection is improved
approximately 10 fold by the use of two ion exchange enhancement columns inserted in
series between the separating column and the detector. The first enhancement column
converts carbonic acid to potassium bicarbonate and the second enhancement column
converts the potassium bicarbonate to potassium hydroxide.
The plastic separating column was 7.5×100mm and was packed with a cation-
exchange resin in the H
+
form TSK SCX 5µm (polystyrene divinyl benzene copolymer-
based material with a high cation exchange capacity).
The first enhancement column was constructed of plastic (4.6×50mm) and packed with
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