Chemistry Reference
In-Depth Information
6
AutoAnalyzer
46.0
±1.24
0.0
±2.7
95.7
±1.47
−0.9 −2.4
8.24
±0.60
−
7
AutoAnalyzer
45.8
±1.57
−0.4 −3.8
97.2
±1.57
+0.7
+2.4
8.60
±0.52
+
8
AutoAnalyzer
45.0
±0.20
−2.2 −2.6
95.2
±0.27
−1.4 −1.6
9.02
±0.43
+
9
AutoAnalyzer
46.1
±0.43
+0.2
+1.2
97.1
±0.17
+0.6
+0.8
8.48
±0.38
−
10
SMA
AutoAnalyzer
46.2
±0.43
+0.4
+1.4
b
b
b
8.6
±0.52
+
Average of all
laboratories
46.0
0.0
-
96.5
-
-
8.58
Concentration found by
WRC
-
-
96.2
-
-
8.48
a
The figures after ± sign are the 90% confidence limits of the means.
b
This laboratory originally conducted the analytical quality control work on another AutoAnalyzer
work on changing to the present system. Insufficient river water A sample remained for work on the
first of the regular 'follow-up' checks showed the bias target to be met
Source: Reproduced with permission from the Royal Society of Chemistry [165]
Levy [170] overcomes this problem by carrying out the reaction at a temperature close to
0°C and sweeping unhydrolysed chlorine out of solutions with a purge of nitrogen before
commencing the determination of chloride ions.
Coulometric titration with dead stop end-point detection has been used for the
determination of down to 0.3mg L
−
1 chloride in acetic acid and nitric acid media [24]
and in methanol-nitric acid medium [171].
Interstitial chloride in very low volumes of pore waters from oil shales rocks has been
determined by coulometric titration [172].
2.17.2
Spectrophotometric methods
Dojlido and Bierwagen [173] have described an automated procedure utilising an
autoanalyser for the determination of chloride in non saline water. The method is based
on the displacement by chloride ions of thiocyanate ions from mercuric thiocyanate and
subsequent Spectrophotometric determination of thiocyanate as ferric thiocyanate. The
standard deviations are ±0.36 and ±0.75mg L
−1
for 8.9 and 34.5mg L
−1
chloride ion
concentration.
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