Analysis of Oxyhalides and Anions in Tap Water (SI-35 4D)

Chloric acid should be analyzed by ion chromatography for water quality control, in accordance to the Ministry of Health, Labor and Welfare in Japan. The method states an addition of 1mL ethylenediamine solution (50mg/mL) to 1L of sample collected. This prevents chlorous acid from reacting with residual chlorine to form chloric acid. Oxyhalides and anions were analyzed using IC SI-35 4D (a column for rapid oxyhalides analysis).

Sample: 20μL each

Std. containing EDA 50mg/L

1. F^– 2mg/L,  2. ClO₂^– 1mg/L,  3. BrO₃^– 1mg/L 4. Cl^– 10mg/L 5. NO₂^– 5mg/L 6. Br^– 10mg/, 7. ClO₃^– 1mg/L,  8. NO₃^– 30mg/L, 9. HPO₄^2- 15mg/L,

10. SO₄^2- 40mg/L

Tap water containing

EDA 50mg/L

1. F^–,  4. Cl^–,  8NO₃^– , 10. SO₄^2-

Column       : Shodex IC SI-35 4D (4.0mmI.D. x 150mm)
Eluent       : 3.6mM Na2CO3 aq.
Flow rate    : 0.6mL/min
Detector     : Suppressed conductivity
Column temp. : 45°C