Performance of Monolithic Silica Capillary Columns with Increased Phase Ratios and Small-Sized Domains
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- 作者：Takeshi Hara ; Hiroshi Kobayashi ; Tohru Ikegami ; Kazuki Nakanishi ; Nobuo Tanaka
- 刊名：Analytical Chemistry
- 出版年：2006
- 出版时间：November 15, 2006
- 年：2006
- 卷：78
- 期：22
- 页码：7632 - 7642
- 全文大小：1036K
- 年卷期：v.78,no.22(November 15, 2006)
- ISSN：1520-6882
文摘
Monolithic silica capillary columns for HPLC were prepared from tetramethoxysilane to have smaller sizeddomains and increased phase ratios as compared toprevious materials, and their performance was evaluated.The monolithic silica columns possessed an externalporosity of 0.65-0.76 and a total porosity of 0.92-0.95and showed considerably higher performance and greaterretention factors in a reversed-phase mode after chemicalmodification than columns previously reported. An octadecylsilylated monolithic silica column with the smallestdomain size (through-pores of ~1.3 
m and silica skeletons of ~0.9 m) showed a plate height of less than 5m at optimum linear velocities (u) of 2-3 mm/s in 80%acetonitrile for a solute having retention factors of ~1, and~7 m at u = 8 mm/s. With a permeability similar to thatof a column packed with 5-m particles, the monolithicsilica columns were able to attain column efficienciescomparable to that of particulate columns packed with2-2.5-m particles, and showed performance in the"forbidden region" for the previous columns. The performance of the monolithic column can be compared favorably with that of a particle-packed column when 15 000-30 000 or more theoretical plates are desired at apressure drop of 20-40 MPa or lower. The increasedhomogeneity of the co-continuous structures, in additionto the small-sized domains, contributed to the higherperformance as compared to previous monolithic silicacolumns.
m and silica skeletons of ~0.9 m) showed a plate height of less than 5m at optimum linear velocities (u) of 2-3 mm/s in 80%acetonitrile for a solute having retention factors of ~1, and~7 m at u = 8 mm/s. With a permeability similar to thatof a column packed with 5-m particles, the monolithicsilica columns were able to attain column efficienciescomparable to that of particulate columns packed with2-2.5-m particles, and showed performance in the"forbidden region" for the previous columns. The performance of the monolithic column can be compared favorably with that of a particle-packed column when 15 000-30 000 or more theoretical plates are desired at apressure drop of 20-40 MPa or lower. The increasedhomogeneity of the co-continuous structures, in additionto the small-sized domains, contributed to the higherperformance as compared to previous monolithic silicacolumns.