Continuous bed columns containing sol-gel bonded large-pore octadecylsilica for capillary electrochromatography

Tang, Qinglin; Wu, Nan; Lee, Milton L.

doi:10.1002/(sici)1520-667x(1999)11:7<550::aid-mcs8>3.0.co;2-b

Cited by 29 publications

(10 citation statements)

References 24 publications

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“…Before packing, the fused silica capillaries were washed with 1 M KOH and water, respectively, and dried with w x nitrogen at 120ЊC, according to Ref. 13 . A 15% sol Ž solution 200 L methanol, 30 L TMOS, 30 L .…”

Section: Methodsmentioning

confidence: 99%

Nonaqueous electrochromatography on continuous bed columns of sol-gel bonded large-pore C30 material: Separation of retinyl esters

2000

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A nonaqueous electrochromatographic reversed‐phase separation method for retinyl esters using continuous bed columns has been developed. The packing material was C30 modified material large‐pore silica (5 μm Nucleosil 4000 Å). The continuous bed columns were prepared by sol–gel bonding in 180 μm inside diameter fused silica capillaries. The mobile phase consisting of 2.5 mM lithium acetate in N,N‐dimethylformamide‐acetonitrile‐methanol (2+7+1, v/v) gave rise to an electroosmotic flow of 1 mm/s at 350 V/cm and 40°C. Using a 36 cm effective length column separation of the commercially available and synthesized standards (all‐trans‐retinyl acetate, palmitate, heptadecanoate, stearate, oleoate, and linoleoate) was obtained within 12 min. Separation of isomeric retinyl palmitate (13‐cis‐ and all‐trans‐retinyl palmitate) was also obtained. The selectivity was found to be temperature dependent in the temperature range investigated (30–60°C). The within‐day and between‐day variations (n=3) of retention times of all‐trans‐retinyl palmitate were 0.2% relative standard deviation (RSD) and <2.5% RSD, respectively. Further, the within‐day and between‐day variations (n=3) of peak areas were in both cases <4% RSD using injection. The column examined was stable for more than 1 month of extensive use. Liver extracts from arctic seal were analyzed. © 2001 John Wiley & Sons, Inc. J Micro Sep 12: 561–567, 2000

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Section: Methodsmentioning

confidence: 99%

Nonaqueous electrochromatography on continuous bed columns of sol-gel bonded large-pore C30 material: Separation of retinyl esters

2000

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“…The second approach to entrap the chromatographic particles is by introducing the entrapping solution after the column has been packed [49,98,99,159]; the column is then dried, after which the temporary retaining frit (originally used to pack the column) is eliminated and the column cut to the desired length. The method by Remcho and Chirica [98] makes use of silicate sol solutions to fill the pressure-packed capillaries with subsequent heating.…”

Section: Particle Entrapmentmentioning

confidence: 99%

“…The columns are then cured with 0.1 M ammonium hydroxide and dried at 160 o C to produce monolithic structures with reported efficiencies similar to those of packed columns, although with reduced retentive characteristics. Lee©s group [49,99,159], on the other hand, first packed the capillary using a CO 2 slurry packing method and then filled the capillary with a sol solution prepared with tetramethoxysilane and ethyltrimethylsilane. The column filled with the sol solution was dried using supercritical CO 2 for 5 h at 40 o C followed by further drying at 120 o C and 250 o C for the same amount of time.…”

Section: Particle Entrapmentmentioning

confidence: 99%

Recent progress in capillary electrochromatography

et al. 2000

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Capillary electrochromatography (CEC) continues to captivate many separation scientists. A remarkable activity is apparent from the numerous publications in the literature using CEC. A review of the most recent progress in CEC is presented herein, covering an extensive fraction of the literature on CEC published from the year 1997 until the beginning of 2000. Most of the recent developments have concentrated on column technology.

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“…Finally, tuning retention behavior is much more difficult than with particulate packings, that can easily undergo numerous (surface) reactions prior to packing into a capillary. Sol-gel bonded particle loaded columns form an intermediate solution between monolithic and classically packed columns [18,19]. Starting with a polymerization mixture containing stationary phase particles, a monolithic column is obtained containing a large fraction of presynthesized particles.…”

Section: Introductionmentioning

confidence: 99%

Novel approach for fritless capillary electrochromatography

Baltussen¹,

Dedem²

2002

Electrophoresis

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At present, the main limitation for the further adoption of capillary electrochromatography (CEC) in the (routine) laboratory is caused by the lack of reproducible and stable columns. The main source of column instability is concentrated in the frits needed to retain the packed bed inside the CEC capillary. The sintering process used to prepare the frits can be rather problematic and irreproducible, particularly for small stationary phase particles and wide column diameters. Since the (surface) composition of the frits is different from the bulk stationary phase packing, different electroosmotic flow (EOF) velocities are generated. This effect is assumed to be primarily responsible for rapid column destruction. In this contribution, a novel approach for the preparation of fritless CEC capillaries is presented and evaluated. Using 5 microm Hypersil ODS particles, separation efficiencies in the range of 130,000-200,000 plates/m were obtained. In a 100 microm inner diameter packed column, electrical currents up to 50 microA could be tolerated without negative effects such as bubble formation. The prepared CEC columns were found to be stable and could easily be operated continuously for several days without column damage. An additional advantage of the proposed tapering approach is that application of pressure on the in- and outlet vial during separation was not required to prevent bubble formation.

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Continuous bed columns containing sol-gel bonded large-pore octadecylsilica for capillary electrochromatography

Cited by 29 publications

References 24 publications

Nonaqueous electrochromatography on continuous bed columns of sol-gel bonded large-pore C30 material: Separation of retinyl esters

Nonaqueous electrochromatography on continuous bed columns of sol-gel bonded large-pore C30 material: Separation of retinyl esters

Recent progress in capillary electrochromatography

Novel approach for fritless capillary electrochromatography

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