Multianion analysis, applications of ion chromatography - Determination of Anions in Natural and Treated Waters - page 681

12.6 Potable waters
12.6.1 Chloride, fluoride, nitrate, nitrite, phosphate and sulphate
The method [60] described in section 12.4.1 for the determination of these anions in
rainwater has also been applied to the analysis of potable water, as has the Environmental
Protection Agency Standard method described in section 12.2.1 [16].
12.6.2 Chloride, bromide, nitrate, phosphate and sulphate
The techniques described respectively, in sections 12.2.1 and 12.4.1 for the determination
of these anions in non saline waters [10] and rainwater [60] have been applied to the
analysis of potable waters.
12.6.3 Bromide, nitrite, nitrate and sulphate
In studies of the formation of bromoforms produced during the disinfection of water
supplies it is necessary to have a method capable of determining bromide ion at the µg
L −1 level. Morrow and Minear [71] have developed an ion chromatographic procedure
using a concentrator column to improve sensitivity. This analysis was carried out on a
Dionex model 125 ion chromatograph equipped with concentrator column in place of an
injection loop, coupled with an autosampler, which allowed detection at the µg L −1 level.
A concentrator column is a short separator column used to strip ions from a measured
volume of matrix leading to a lowering of detection limits by several orders of
magnitude.
To initiate an analysis the system lines were flushed with sample for 2min prior to
loading via the auto sampler. A 50ml volume of sample was then loaded onto the
concentrator, via the autosampler, at 100% A (7.67ml min − 1 ). The concentrated sample
was then flushed (injected) into the