Preparation, chromatographic evaluation and application of adenosine 5′-monophosphate modified ZrO2/SiO2 stationary phase in hydrophilic interaction chromatography

The zirconia-coated silica (ZrO 2 /SiO 2 ) material was obtained by coupling layer-by-layer (LbL) self-assembly method and sol–gel technology, to take dual advantages of the suitable porous structure of SiO 2 and basic resistance of ZrO 2 . Adenosine 5′-monophosphate (5′-AMP) was then self-assembled onto ZrO 2 /SiO 2 via Lewis acid–base interaction, generating 5′-AMP-ZrO 2 /SiO 2 . The chromatographic properties of 5′-AMP-ZrO 2 /SiO 2 were systemically studied by evaluating the effect of acetonitrile content, pH and buffer concentration in the mobile phase. The results demonstrated that the 5′-AMP-ZrO 2 /SiO 2 possessed hydrophilic interaction chromatographic (HILIC) property comprising hydrophilic, hydrogen-bonding, electrostatic and ion-exchange interactions. For basic analytes, the column efficiency of ZrO 2 /SiO 2 and 5′-AMP-ZrO 2 /SiO 2 was superior to the bare ZrO 2 , and different selectivity was obtained after the introduction of 5′-AMP. For acidic analytes, good resolution was obtained on 5′-AMP-ZrO 2 /SiO 2 while the analysis failed on the bare ZrO 2 column owing to strong adsorption. Hence, the proposed 5′-AMP-ZrO 2 /SiO 2 had great potential in analyzing acidic compounds in HILIC mode. It was an extended application of ZrO 2 based SP.