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[Comparison in hydrophobic selectivity for two types of reversed-phase high performance liquid chromatography packing material].

Two types of novel reversed-phase packing materials were made by adding TiO2/ SiO2 (or ZrO2/SiO2) and octadecyltrichlorosilane into toluene with stirring and refluxing for 36 h. TiO2/SiO2 and ZrO2/SiO2 particles were prepared by a layer-by-layer self-assemble technique and consist of micrometer-sized silica spheres as cores and nanometer-sized zirconia or titania as surface coating. The carbon loading of C18-bonded TiO2/SiO2 was 11.51% and that of C18-bonded ZrO2/SiO2 was 9.62%. The hydrophobic selectivity and sensitivity were studied respectively and compared in details; the results showed that the packing supports both acted as true reversed chromatographic stationary phase with similar hydrophobic selectivity. The chromatographic behaviors of the two types of novel reversed-phase packing material were evaluated with nine aromatic compounds. The chromatographic studies showed that either of the packing materials would be a good choice to separate aromatic compounds, however, the selectivity of C18-bonded TiO2/SiO2 was a little better than that of C18-bonded ZrO2/SiO2.