Preparation And Properties Of Novel High Column Efficiency And High Permeability Octadecyl Bonded Silica Monolithic Columns And Polymer Monolithic Columns

The surface bonded octadecyl(C18)reversed phase silica monolith and polymer monolith were prepared respectively.The permeability,vandermt curve and performance of two types of monolithic columns were compared.For the monolithic silica column,the column efficiency is as high as 435000 theoretical plates/m.so far,there is no report that the monolithic silica column has achieved this column efficiency.Seven neutral substances have been separated on the monolithic C18 silica column within 2.7 min,realizing efficient and rapid separation.In order to improve the permeability of polymer monolithic stationary phase,the permeability and column efficiency of polymer monolithic stationary phase were higher than those reported in literature by changing the proportion of pore forming agent.Comparing the vandermt curves of two kinds of silica monolithic columns and polymer monolithic columns,the minimum tray heights of them are 2.67 ?m and 2.84 ?m respectively.The tray height of the sample on the silica gel monolithic column almost does not increase with the increase of the flow rate,which indicates that the mass transfer resistance of the sample on the silica gel monolithic column is smaller and more conducive to rapid analysis.Based on the characteristics of high column efficiency of silica monolithic column,we analyzed the isomers of butylbenzene which are difficult to be separated on ordinary chromatographic column.The results show that the four isomers can basically achieve baseline separation,which shows the strong separation ability of the high column efficiency silica monolithic column prepared in this experiment.It was observed that the column efficiency decreased with the increase of injection times.The injection end of the capillary was observed under microscope before and after use.It is found that the decrease of column efficiency with the increase of injection times is due to the swelling of polyimide coating on the outer wall of the capillary,and a solution to remove the polyimide coating on the outer wall of the capillary before use is proposed.After removing the polyimide coating on the outer wall of the capillary at the 0.30 cm injection end,the above problems were completely solved.