Dionex Corporation

Other

Roche Diagnostics Gmbh

F. Hoffmann-la Roche Ag

Jinhua Chen

Christopher A Pohl

Yan Liu

Xiaodong Liu

Thomas W Bell

Alisher B Khasanov

Jun Cheng

Zhongqing Lu

L Andy Woodruff

Andy L Woodruff

An anion exchange for separating a plurality of carbohydrates includes a negatively charged substrate particle. A base polymer layer includes a first plurality of quaternary amines. The polyalkylpolyamine polymer layer is covalently attached to the base condensation polymer layer. The polyalkylpolyamine polymer layer includes a polymeric branch structure that includes a second plurality of quaternary amines. A density of the second plurality of quaternary amines increases in a direction away from the base condensation polymer layer. The anion exchange stationary phase does not have a hydroxy group spaced apart from any one of the first or the second plurality of quaternary amines by an ethyl group.

Anion exchange stationary phases based on a polyalkylpolyamine polymer layer

The current invention provides compositions, which are useful as stationary phases for a variety of chromatographic applications, such as high performance liquid chromatography (HPLC) and solid-phase extraction (SPE). The compositions include a porous solid support (e.g., silica gels, silica monoliths or synthetic organic resins) having an exterior surface and pore openings defined by 'interior walls'. To the solid support are covalently bound organic ion-exchange ligands (e.g., silyl ligands), which incorporate at least one ion-exchange group (e.g., ionic or ionizable group). The compositions further include micro-particles (e.g., latex particles) incorporating ion-exchange groups having a charge that is opposite to the charge found on the support. The micro-particles are bound to the exterior surface of the support (e.g., via electrostatic forces). The micro-particles have a size that is sufficient to minimize the number of particles that can enter the pores of the support thereby reducing or essentially preventing binding of the micro-particles to the interior walls of the pores. While the pores are essentially too small for the micro-particles, they can still be accessed by the analytes present in a chromatographic sample. The physical separation of ion-exchange groups located within the pores and the surface of the micro-particles, respectively, prevents reactions (e.g., formation of salt-bridges) between the oppositely charged groups and provides compositions with both anion-exchange and cation-exchange capabilities within the same stationary phase. The ligands bound to the solid support can optionally include additional (e.g., reverse-phase) functionalities creating multi-modal (e.g., trimodal) stationary phases.

Functionalized substrates with ion-exchange properties

The present invention provides an agglomerated multimodal chromatographic medium. the medium of the invention includes groups active in anion exchange, cation exchange and hydrophilic interaction chromatographic modalities. The invention provides methods of making these media and using them in separations of analytes. Also provided are separations devices incorporating the medium and systems incorporating these separations devices.

HILIC/anion-exchange/cation-exchange multimodal media

The current invention provides compositions, which are useful as stationary phases for a variety of chromatographic applications, such as high performance liquid chromatography (HPLC) and solid-phase extraction (SPE). The compositions provide both strong aromatic and hydrophobic interactions with components of a sample. Moreover, the invention provides compositions of new silanes, their immobilization on a solid substrate, such as silica, to form new stationary phases.

Functionalized substrates with aromatic stacking properties

The current invention provides compositions, which are useful as stationary phases for a variety of chromatographic applications, such as high performance liquid chromatography (HPLC). The compositions include a substrate (e.g., silica gel), covalently bound to a compound, which includes both a hydrophobic moiety and a hydrophilic moiety, which is preferably a 1,2-diol moiety. The hydrophobic moiety is sufficiently hydrophobic for the compositions to exhibit reversed phase characteristics and typically incorporates at least 5 carbon atoms in sequence. Based on having both hydrophilic and hydrophobic functionalities, the new stationary phases exhibit unique chromatographic properties. For example, these media can be used in either hydrophilic (HILIC) mode, in which the mobile phase includes a high percentage of an organic solvent, or in reversed phase mode, in which the mobile phase contains a higher percentage of an aqueous solvent. The current invention also provides methods of making and using the compounds and compositions of the invention.

Compositions useful as chromatography stationary phases

The present invention relates to compounds and more particularly to compounds which are useful for the determination of bicarbonate and the delivery of bicarbonate to a non-aqueous solution. The invention further relates to an optical sensor for the determination of bicarbonate in a liquid sample.

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San Jose, CA, United States of America

Jinhua Chen