Monovalent and divalent cation standards were analyzed using IC YK-421 (a column for cation analysis).

(Advantage of Phosphoric acid eluent)
The standard eluent of IC YK-421 is tartaric acid / dipicolinic acid eluent, but the storage stability of this eluen is poor and The solubility of the reagents used for eluent is also low, It was not possible to prepare the concentrated solution. On the other hand, phosphoric acid eluent is possible to save about one week and the concentrated solution (1 mol/L) can be sotred for a long term (six months).
(The difference)
(1) Mg²⁺ ion elutes after the Ca²⁺ ions in the case of tartaric acid / dipicolinic acid-based eluent, but elution order of Ca²⁺ ion and Mg²⁺ ion is reversed in the case of phosphoric acid-based eluent.
(2) Transition metal ions are eluted at a position of Vo in the tartaric acid / dipicolinic acid eluent, but eluted collectively between Ca²⁺ ion and Mg²⁺ ion in the phosphoric acid-based eluent. Therefore, we do not recommend the use of phosphate eluent, if you want to analyze a sample containing a large amount of transition metal ions.
(3) Background of phosphoric acid eluent is higher than tartaric acid / dipicolinic acid eluent.

Please refer to YK-421 (tartaric acid + dipicolinic acid eluent)


Sample : 20 μL
1. Li⁺ 2 mg/L
2. Na⁺ 10 mg/L
3. NH₄⁺ 10 mg/L
4. K⁺ 20 mg/L
5. Mg²⁺ 10 mg/L
6. Ca²⁺ 20 mg/L

Column       : Shodex IC YK-421 (4.6 mm I.D. x 125 mm)
Eluent       : 4 mM H3PO4 aq.
Flow rate    : 1.0 mL/min
Detector     : Non-suppressed conductivity
Column temp. : 40 °C