Continuous stationary phase gradients for planar chromatographic media

Kannan, Balamurali; Marin, Michael A.; Shrestha, Kushal; Higgins, Daniel A.; Collinson, Maryanne M.

doi:10.1016/j.chroma.2011.10.075

Cited by 23 publications

(49 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2. The shape of the gradient profile depends on factors such as reaction kinetics, silane concentrations, infusion rate, order of infusion, and the presence and extent to which the plate has already been modified [23][24][25]. As expected, for the unmodified, as-received plates, negligible signal was observed (data not shown).…”

Section: Characterization Of Amine and Phenyl Gradient And Uniformly supporting

confidence: 55%

“…In this work, amine and phenyl silane gradients were fabricated on silica TLC plates using CRI [23][24][25]. In this method, a solution containing either the amine or the phenyl silane is infused at a fixed rate into a graduated cylinder holding the vertically aligned TLC plate.…”

Section: Fabrication Of Amine and Phenyl Modified Tlc Platesmentioning

confidence: 99%

“…We have also fabricated two-component gradients using controlled rate infusion (CRI) [23][24][25] and infusion-withdrawal dip coating (IWDC) [26][27][28]. These two methods involve a variation of the sol-gel process [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

“…These two methods involve a variation of the sol-gel process [29][30][31]. In CRI, a reactive organoalkoxysilane is gradually infused at a controlled rate into a reaction vessel where it reacts with Si OH groups on the surface of a siloxane-coated substrate in a time-dependent fashion [23][24][25]. Gradient formation is governed by the rate of infusion, the rate of reaction, and the concentration of the silane.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Amine-phenyl multi-component gradient stationary phases

Dewoolkar

Kannan

Ashraf

et al. 2015

Journal of Chromatography A

Self Cite

View full text Add to dashboard Cite

Continuous multi-component gradients in amine and phenyl groups were fabricated using controlled rate infusion (CRI). Solutions prepared from either 3-aminopropyltriethoxysilane (APTEOS) or phenyltrimethoxysilane (PTMOS) were infused, in a sequential fashion, at a controlled rate into an empty graduated cylinder housing a vertically aligned thin layer chromatography (TLC) plate. The hydrolyzed precursors reacted with an abundance of silanol (SiOH) groups on the TLC plates, covalently attaching the functionalized silane to its surface. The extent of modification by phenyl and amine was determined by the kinetics of each reaction and the exposure time at each point along the TLC plate. The local concentrations of phenyl and amine were measured using diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy, respectively. The profile of the multi-component gradients strongly depended on the order of infusion, the direction of the gradient and the presence of available surface silanol groups. A slightly higher amount of phenyl can be deposited on the TLC plate by first modifying its surface with amine groups as they serve as a catalyst, enhancing condensation. Separation of water- and fat-soluble vitamins and the control of retention factors were demonstrated on the multi-component gradient TLC plates. Uniformly modified and single-component TLC plates gave different separations compared to the multi-component gradient plates. The retention factors of the individual vitamins depended on the order of surface modification, the spotting end, and whether the multi-component gradients align or oppose each other.

show abstract

Section: Characterization Of Amine and Phenyl Gradient And Uniformly supporting

confidence: 55%

Section: Fabrication Of Amine and Phenyl Modified Tlc Platesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Amine-phenyl multi-component gradient stationary phases

Dewoolkar

Kannan

Ashraf

et al. 2015

Journal of Chromatography A

Self Cite

View full text Add to dashboard Cite

show abstract

“…To our knowledge, only one report has appeared on a continuous stationary phase gradient on a particle packed column. 13 In that work, the stationary phase gradient was created on a commercially modied C 18 column via the timedependent acid hydrolysis and hydrolytic cleavage of C 18 ligands. 13 For columns that have already been modied with an organic constituent, this is a viable approach for creating a stationary phase gradient on a packed column.…”

Section: Introductionmentioning

confidence: 99%