Anions in non saline waters - Determination of Anions in Natural and Treated Waters - page 276

Fig. 2.45 Recorder tracings of selenium analysis of a river water sample: (A)
Se(−II, 0) plus Se(IV) procedure 2; (B) total Se (procedure 2): (a) 4,
6-dibromopiazselenol
Source: Reproduced with permission from the American Chemical
Society [673]
solution and selenium(VI) is reduced to the same state by bromine/ bromide redox buffer
solution and determined as the piazselenol as above.
As an example, the gas chromatograms of selenium in river water are shown in A and
B and Fig. 2.45 respectively. Selenium(VI) is calculated from the difference between the
peak heights of 4, 6-dibromopiazselenol in A and B. The total amount of selenium in
river water varied largely, eg from 16 to 230ng L −1 .
2.89.7 Miscellaneous
Brimmer et al. [665] have carried out an investigation of the quantitative reduction of
selenate to selenite in aqueous solutions.
2.89.3 Preconcentration
The preconcentration of selenite is discussed in section 15.1.9.