Simultaneous separation of common mono- and divalent cations on silica gels modified with aluminium and zirconium

The modification of silica gel with aluminium and zirconium can be used for the preparation of advanced silica-based cation-exchange stationary phases for use in ion chromatography with conductimetric detection (IC-CD) for cations. Silica gels modified with aluminium (Al-silica) and zirconium (Zr-silica) act as cation-exchangers under strongly acidic conditions. Highly sensitive indirect conductimetric detection and excellently simultaneous separation for common mono- and divalent cations (Li+, Na+, NH4 +, K+, Mg2+ and Ca2+) can be achieved on the Al-silica and Zr-silica columns in IC-CD by using acidic eluents containing 15-crown-5 (1,3,7,10,13-pentaoxacyclopentadecane). The Al-silica and Zr-silica can also be applied successfully as cation-exchange stationary phases in ion-exclusion chromatography for the separation of various aliphatic and benzenecarboxylic acids. © 2001 Elsevier Science B.V.