Effect of pH on Retention Time (1) (I-524A)

Anion standards were analyzed using IC I-524A. This figure shows the effect of pH on retention time with a 2.5mM phthalic acid eluent. Generally, the retention time decreases with the increase of pH. A sharp peak of MoO₄^2- cannot be obtained below pH5.0, neither CrO₄^2- below pH6.0, nor H₂PO₄^- can be obtained above pH4.2 or F^- above pH4.5.


Sample :
Br^-
Cl^-
F^-
I^-
NO₃^-
NO₂^-
ClO₄^-
H₂PO₄^-
SO₄^2-
SCN^-
S₂O₃^2-
MoO₄^2-
CrO₄^2-

Column       : Shodex IC I-524A (4.6mmID*100mm)
Eluent       : 2.5mM Phthalic acid(pH variable)
Flow rate    : 1.2mL/min
Detector     : Non-suppressed coductivity
Column temp. : 40deg-C