Effects of eluent pH on the elution of each anion using IC NI-424 (an anion analysis column for non-suppressor method) are shown. When the pH of the eluent is increased, the retention time for the anions is decreased.


Sample : 20 μL
H₂PO₄^- 10 mg/L
F^- 10 mg/L
Cl^- 10 mg/L
NO₂^- 10 mg/L
Br^- 10 mg/L
NO₃^- 10 mg/L
I^- 20 mg/L
SO₄^2- 10 mg/L
S₂O₃^2- 50 mg/L
SCN^- 50 mg/L
ClO₄^- 50 mg/L

Column       : Shodex IC NI-424 (4.6 mm I.D. x 100 mm)
Eluent       : 8 mM 4-Hydroxybenzoic acid + 2 mM Phenylboronic acid
               + 0.005 mM *CyDTA (pH adjusted with Bis-Tris)
Flow rate    : 1.0 mL/min
Detector     : Non-suppressed conductivity
Column temp. : 40 °C

*CyDTA: trans-1,2-Diaminocyclohexane-N,N,N',N'-tetraacetic acid