Chemistry Reference
In-Depth Information
8.6.2
Atomic absorption spectroscopy
Martin and Riley [20] used this technique to determine hexavalent chromium in waste
waters.
8.6.3
Differential pulse polarography
Harndorf and Janner [21] applied this technique to waste water samples and investigated
interference by other cations.
Table 8.8
Results of analysis by present method in comparison with diphenylcarbazide
method
Sample
No.
Water
taken ml
Chromium found
by present method
µg
Chromium content
in water sample
mg L
−1
Chromium found by
diphenylcarbazide method
mg L
−1
1
20.0
2.30
0.115
0.1 10
2
10.0
6.00
0.600
0.550
3
2.0
5.56
2.78
2.65
4
4.0
7.40
1.82
1.73
5
2.5
9.1
3.64
3.76
Source: Reproduced with permission from Springer Verlag [17]
8.6.4
Miscellaneous
Pavel
et al.
[22] examined the behaviour and persistence of trace amounts of chromium
(VI) in waste water samples as a function of pH, container material, initial concentration
and temperature. Based on these results they devised a method for preserving the
hexavalent form of chromium; following adjustment to pH 7-8, addition of 10% v/v of a
solution containing 0.5M sodium bicarbonate and 0.1M EDTA (disodium salt) reduced
losses of chromium(VI) to less than 20% after 7 days, compared with a 60-80% loss in
unprotected samples.
8.7
Cyanate
8.7.1
Spectrophotometric method
The application of this technique is discussed under multianion analysis in section
14.2.3.2.
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