Preparation and evaluation of p-tert-butyl-calix[8]arene-bonded silica stationary phase for high performance liquid chromatography

A new p-tert-butyl-calix[8]arene-bonded silica gel stationary phase was syn thesized through heterogeneous functionalisation of suspended porous silica . A characterization of its structure was carried out by using elemental an alysis, FTIR and C-13 solid State NMR spectroscopy. Chromatographic perform ance of the new packing material was investigated by employing polycyclic a romatic hydrocarbons (PAHs) as probes and using methanol-water as mobile ph ase. The investigations show that the new stationary phase behaves asa reve rsed phase stationary phase. The liquid chromatographic separation of PAHs solutes on the new bonded phase was compared with that on a p-tert-butyl-ca lix[4]arene-bonded silica stationary phase. The new p-tert-butyl-calix[8]ar ene-bonded phase exhibited higher retention and better separation selectivi ty, although the carbon content and coverage of the new packing material wa s lower than that of the p-tert-butyl-calix[4]arene bonded silica stationar y phase. A possible retention mechanism for the new packing material was al so proposed.