Anions in non saline waters - Determination of Anions in Natural and Treated Waters - page 181

14.4.1.2.

2.50.6 Inductively coupled plasma atomic emission spectrometry
Miyazaki and Brancho [346] preconcentrated iodide by conversion to iodine and
extraction into xylene. The extract was determined at 172.28nm using inductively
coupled plasma atomic emission spectrometry. Iodate was reduced to iodide which was
then treated in the same way to give a total iodide plus iodate content. Detection limits
were, respectively, 8.3 and 21µg L −1

for iodate and iodide. Large concentrations of

bromide interfere.
Michlewicz and Carnahan [133] give details of a method for the determination of
iodide based on pneumatic nebulisation and ultrasonic neutralisation of the sample into a
helium microwave induced plasma. The detection limit was 3mg L −1 bromide.
Potassium, magnesium, sodium and lithium interfered moderately with pneumatic
nebulisation but significantly with ultrasonic nebulisation.

2.50.7 Cathodic stripping voltammetry
The application of this technique is discussed under multianion analysis in section
14.9.1.2.

2.50.8 Polarography
In the polarographic determination [364] of 0.2µmol quantities of iodide in non saline
waters, the iodide was oxidised to iodate with sodium hypochlorite and the excess
oxidant destroyed with sodium sulphite.
Iodate was determined by differential pulse polarography and the concentration of
iodide calculated as the difference between the concentrations of iodate in a sample
before and after oxidation.
L uther et al. [ 365] carried out a direct determination of down to 12ng L −1 of iodide in
seawater using cathode stripping square wave voltammetry.
The application of this technique is also discussed under multianion analysis in section
14.10.1.1.

2.50.9 Potentiometric method
Bardin and Tolstousov [352] used a flow-type concentration cell with two silver-silver
iodide electrodes for the potentiometric determination of down to 3µg L −1 of iodide in
non saline waters. At iodide concentrations of up to 0.6µmol L −1 the variation in EMF of
the cell is nearly proportional to the concentration of iodide.
Zernalova and Senyavin [327] examined conditions for the potentiometric
determination of iodide in non saline water.

2.50.10 Ion selective electrodes
Yuan et al. [366] used schiff base complexes of cobalt(II) as neutral carriers for highly