Anions in surface, ground, mineral, borehole and pure waters - Determination of Anions in Natural and Treated Waters - page 459

6.2.8 Sulphide
6.2.8.1 Inductively coupled plasma atomic emission spectrometry
Lewin et al. [21] have described a rapid and simple inductively coupled plasma atomic
emission spectrometric technique for determinant dissolved sulphide at the ppb level in
groundwater. Sulphide is stabilised on sampling by addition of potassium hydroxide and
is later converted to hydrogen sulphide under acidic conditions and stripped from the
solution in a gas-liquid separator by a stream of argon. The emission intensity is
monitored at 180.7nm. Dissolved sulphate does not interfere and spectral interference
from calcium is avoided.
6.2.8.2 Miscellaneous
Baedecker and Cozzarelli [22] have reviewed the determination and fate of unstable
sulphide in ground waters.
6.2.9 Multianion analysis
6.2.9.1 Ion chromatography: selenate, selenite and arsenate
Hoover and Jager [23] have discussed the determination of selenite together with other
anions (selenate and arsenite) in potable and groundwaters by ion chromatography.
6.3 Mineral waters
6.3.1 Arsenate
6.3.1.1 Polarography
An indirect polarographic method has been used to determine traces of arsenate in
mineral waters [24]. In this method arsenate is converted to uranyl arsenate which is
filtered off and excess uranyl ion is determined by polarography at −3.60V. Phosphates
interfere in this procedure.
6.3.2 Cyanide
6.3.2.1 Ion selective electrodes
The application of this technique is discussed under multianion analysis in section
14.11.1.1.