E.i. Dupont De Nemours and Company

Hewlett-packard Company

Agilent Technologies, Inc.

Joseph J Kirkland

Wallace W Yau

John B Adams, Jr

Charles H Dilks, Jr

Timothy J Langlois

Jurgen Kohler

Joseph L Glajch

Horacio E Bergna

Ralph K Iler

Ounjie Wang

John W Grant

Qunjie Wang

Highly purified, porous silica microspheres contain functional groups which are capable of selectively binding to reaction impurities, such as excess reactant or reaction by-products, which are contained in a reaction medium. The reaction impurities can thereby be efficiently removed from the reaction medium, providing a convenient method for product purification.

Porous silica microsphere scavengers

The present invention provides propylene-bridged bidentate silane reagents for modifying the surface of liquid chromatography supports, these supports and methods of making and using the same. When bonded to the surface of a support material, the resulting modified support material provides improved properties, such as better separations and more stable support materials, especially when used in liquid chromatography. These bidentate silanes have the general structure: RSiMe(NMe.sub.2)--(CH.sub.2).sub.3 --SiMeR--NMe.sub.2. R is an n-octadecyl group or an n-tetradecyl group, and Me is a methyl group. When reacted with a silica surface, the resulting modified surface has a structure: PSiO--[RSiMe--(CH.sub.2).sub.3 --SiMeR]--OSiP. PSiO is surface-reacted silica.

Propylene-bridged bidentate silanes

The present invention provides propylene-bridged bidentate silane reagents for modifying the surface of liquid chromatography supports, these supports and methods of making and using the same. When bonded to the surface of a support material, the resulting modified support material provides improved properties, such as better separations and more stable support materials, especially when used in liquid chromatography. These bidentate silanes have the general structure: RSiMe(NMe.sub.2)--(CH.sub.2).sub.3 --SiMeR--NMe.sub.2. R is an n-octadecyl group or an n-tetradecyl group, and Me is a methyl group. When reacted with a silica surface, the resulting modified surface has a structure: PSiO--�RSiMe--(CH.sub.2).sub.3 --SiMeR!--OSiP. PSiO is surface-reacted silica.

The present invention provides asymmetric bidentate silane reagents from modifying the surface of liquid chromatography supports, the supports and methods of making and using the same. When bonded to the surface of a support material, the resulting modified support material provides improved properties, such as better separations and more stable support materials, especially when used in liquid chromatography. These bidentate silanes have the general structure: R.sub.1 SiMe(NMe.sub.2)--(CH.sub.2).sub.n --SiMeR.sub.2 (NMe.sub.2). R.sub.1 is an alkyl group having from 1 to 30 carbon atoms, and R.sub.2 is an alkyl group having from 8 to 18 carbon atoms. R.sub.1 is a different alkyl group than R.sub.2. Me is a methyl group, and n has a value 2 or 3. In certain embodiments, R.sub.2 includes at least one functional group. When reacted with a silica surface, the resulting modified surface has a structure: PSiO--�R.sub.1 SiMe--(CH.sub.2).sub.n --SiMeR!--OSiP. PSiO is a surface reacted silica.

Asymmetric bidentate silanes

Chromatographic material comprising porous silica microspheres having silanol-enriched and completely silanized surfaces are disclosed. Processes for preparing the specified chromatographic material are also disclosed.

Porous silica microspheres having silanol-enriched and silanized surfaces

Chromatographic materials comprising porous silica microspheres having silanol-enriched and completely silanized surfaces are disclosed. Processes for preparing the specified chromatographic material are also disclosed.

Porous silica microspheres having a silanol enriched surface

This invention involves unique compositions consisting of substrates coated with organo-silanes that are sterically protected by a single bulky group. This material consists of an appropriate reactive solid to which is attached a silane whose silicon stom is bonded to a functional group that contains a dimethyl-substituted tertiary carbon.

Substrates coated with organo-silanes that are sterically-protected

A bidentate silane containing at least two silicon atoms bridged by certain groups, arranged to form at least a seven member ring system, is formed between the bidentate silane and the atoms to which the silane is covalently attached on the substrate surface.

Structures surface modified with bidentate silanes

This invention relates to unique stable support structures comprising substrates coated with sterically-protecting monofunctional silanes. This structure consists of an appropriate reactive solid to which a monofunctional silane is covalently bonded that contains at least two sterically-protecting groups attached to the silicon atom of the silane.

Substrates with sterically-protected, stable, covalently-bonded

There is disclosed a process for preparing superficially porous macroparticles comprising spray drying a specified well-mixed slurry of core macroparticles, colloidal inorganic microparticles and a liquid and sintering the resulting product to cause a 5%-30% decrease in surface area.

Process for preparing superficially porous supports for chromatography

A plastic ring has a circumferential groove formed in its outer peripheral surface. The ring is fitted in a bowl-type centrifuge rotor such that the ring's outer surface contacts the inner wall of the rotor. The channel is defined by the groove and rotor wall. The rotor is filled with a compensating liquid to reduce centrifugal stress on the plastic and to reduce leakage from the channel.

Apparatus and method for sedimentation field flow fractionation

A free floating plastic channel for sedimentation field flow fractionation is suspended in a centrifuge rotor filled with a compensating liquid. The channel is constructed of a plastic central hub assembly fitted with a plastic outer ring preferably having a lower density than the hub. The outer ring contains a shallow channel on its radially inner surface and is interference-fitted to the inner ring to insure a liquid tight seal at zero force field. With the liquid totally surrounding the hub-outer ring assembly, stresses on the plastic parts are essentially equalized even under high force fields and leakage from the channel at the hub-ring interface is greatly reduced.

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Wilmington, DE, United States of America

Joseph J Kirkland