Composite of ZIF-8 and totally porous silica gel for HPLC stationary phase

Abstract

Abstract Metal-organic frameworks (MOFs) supported on silica gels have been proved to be promising stationary phases for high performance liquid chromatography (HPLC). However, up to now, the stationary phases still face the problems of uneven dispersion of MOFs on traditional spherical silica gels and the poor separation performance. In this work, the effect of the silica gel pore size on the dispersion of ZIF-8 on totally porous silica gel was systematically investigated and the highly uniform dispersion of ZIF-8 was gained on the silica gel with the pore diameter of 80 nm. Moreover, the distribution of ZIF-8 nanoparticles on the surface of wide pore silica could be further improved by adjusting the proportion of DMF and methanol solution. When the well packed ZIF-8@SiO2 composite column was used to separate hydroquinone and p-benzoquinone, its resolution reached an outstanding value of 5.47, while there was no baseline separation on the C18 column. Finally, the separation mechanism was also studied by testing the separation of the mixture of 1-phenylethanol and acetophenone. This work would provide an easy way to disperse MOFs on traditional silica gels and could provide a composite column for separation of hydroquinone and p-benzoquinone.