Seven kinds of anions can be separated using IC NI-424 (an anion analysis column for non-suppressor method) with phthalic acid eluent. Peak height of anions with phthalic acid eluent were around twice higher than chromatogram with hydroxybenzoic acid eluent. On the other hand, anions with phthalic acid eluent were eluted earlier then these peaks from H₂PO₄^- to NO₃^- were closer each other.


Sample : 100 μL each
1. H₂PO₄^- 10 mg/L
2. F^- 1 mg/L
3. Cl^- 1 mg/L
4. NO₂^- 5 mg/L
5. Br^- 5 mg/L
6. NO₃^- 5 mg/L
7. SO₄^2- 5 mg/L

Column       : Shodex IC NI-424 (4.6 mm I.D. x 100 mm)
Eluent       : (A) ; 8 mM 4-Hydroxybenzoic acid + 2.8 mM Bis-Tris
                     + 2 mM Phenylboronic acid + 0.005 mM *CyDTA aq.
               (B) ; 2.1 mM Phthalic acid + 2.9 mM Amino-n-capronic acid
                     + 6 mM Phenylboronic acid aq.
Flow rate    : 1.0 mL/min
Detector     : Non-suppressed coductivity
Column temp. : 40 °C

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