Multianion analysis, applications of ion chromatography - Determination of Anions in Natural and Treated Waters - page 667

in Table 12.14. The proximity of the chromatographic values to the EPA values indicates
that corrections for matrix effects, due to additional constituents present in this standard,
are unnecessary.
The use of concentration columns in conjunction with ion chromatography is one
means of improving the sensitivity of this procedure. Wetzel et al. [58] used this
procedure to obtain determinations down to µg L −1 concentrations of chloride, phosphate,
nitrate and sulphate in rainwater

Table 12.14 Comparison of anion concentrations: chromatographic values vs EPA values

Concentrations (mg L −1 )

Cl − NO 3 − SO 4 −

1. EPA value 4.6 0.34 1.8

Chromatography value
Run 1 5.0 0.32 1.83

Run II 4.84 0.34 1.72

Mean 4.93 0.33 1.78

2. EPA value 2.3 0.17 0.09

Chromatography value
Run 1

2.27 0.16 0.88

Run II 2.39 0.14 0.89

Mean 2.33 0.15 0.89

Source: Reproduced with permission from the Journal of Oceanographic Science [61]

samples. Conductivity detector response is linear with concentrations over the mg L −1 to
µg L −1 range for the determinands examined. It was shown that a 3×50mm peculiar anion
exchange resin with tetraethyl ammonium groups attached to a styrene divinyl benzene
backbone concentrator column can be loaded remotely and stored for at least 7 days
before analysis without significantly affecting ionic determinations.
Sample loading can be performed with the concentrator replacing the injection loop;
sample is then loaded by syringe or by pump. Concentration may also be loaded off line,
disconnected from the ion chromatograph. In the former case, activation of the injection
valve automatically places the concentrator column in line with the separator column. In
the latter case, the concentrator must be manually connected to the flow path before the
separator. After injection, sample ions are separated and detected in the usual manner.
Normal multispecies analysis often requires less than 5min per ion; trace analysis
requires the same time as routine analysis once the concentrator is loaded. Concentrator
loading requires 5-15min per sample.

Reagents