Separation and detection of common mono- and divalent cations by ion chromatography with an ODS column and...

The retention and detection behavior of common mono- and divalent cations (M+, alkali metal (Li+, Na+, K+, Rb+, Cs+) and ammonium ions (NH4+); M2+, alkaline earth metal ions (Mg2+, Ca2+, Sr2+, Ba2+) was examined using an ODS column (150 x 4.6 mm I.D.) and conductivity (CD)/UV detection. The results obtained were as follows: (1) for M+, the mobile phase, 0.1 mM sodium dodecyl sulphate (SDS) + 10 mM HNO3 and indirect CD detection were effective. (2) Addition of Ce(III) in the mobile phase accelerated the elution of both M+ and M2+. The separation of above 10 cations on an ODS column was achieved for the first time without any coelution of cations and disturbance by system peak. Addition of higher SDS resulted in good separation of M+ and M2+ with longer retention times. CD detection was possible for M+ and M2+ and UV detection for M2+. (3) For M2+, the mobile phase, 0.8 mM Ce(III) + 0.1 mM SDS + 1 mM HNO3 and indirect UV detection were effective. The IC methods were applied to real samples.