Cation exchange columns Metrohm

A good general-purpose weak acid cation-exchange column for non-suppressed applications is the Metrosep Cation C 2 column from Metrohm. As the selection of eluents used with this column is quite varied, the reader is referred to Metrohm column literature for specific eluent recommendations. The Metrosep Cation C 2 column is prepared via encapsulation of a porous silica substrate maliec acid copolymer. 

Cation exchangers based on PBDMA-coated silica are offered by a number of companies. Metrohm (Herisau, Switzerland), for example, offers two columns under the trade names Metrosep Cl and C4. The 5 pm Metrosep Cl is considered to be the high-performance column for the simultaneous analysis of mono-and divalent cations with an analysis time of less than 20 min. It can also be used for the separation of various amines, which are typically eluted with a nitric acid eluent. Figure 4.41 shows an example chromatogram obtained under standard chromatographic conditions with an eluent mixture of tartaric acid and pyridine-2,6-dicarboxyiic acid (PDCA) (dipicohnic acid). Under these chromatographic conditions, calcium elutes ahead of magnesium, followed by strontium and barium. This unusual retention behavior can be attributed to the complex-ing properties of pyridine-2,6-dicarboxylic acid. With a pure tartaric acid eluent. 

---