A new approach for the preparation of a hydride-modified substrate used as an intermediate in the synthesis of surface-bonded materials

Abstract

A new approach to produce a hydride-modIfled support which serves as an Intermediate for the synthesis of chromatographic bonded phases Is Investigated. The procedure, referred to as "sllanlzatlon", Involves the controlled deposition of the hydrolysis product of trlethoxysllane (TES) or related silanes to preferentially form an Sl-H monolayer on Inorganic oxide substrates such as silica. Chemical and spectroscopic, as well as thermal, analyses are employed for the characterization of the Intermediate. This synthetic route was developed to Improve an existing method for producing a surface uniformly covered with active sites required for further modification via SIH addition to terminal olefins. With the new approach the time-consuming processes associated with the previous" ' reported chlorination/reduction procedure are eliminated, i addition to Its greater simplicity, sllanlzatlon with TES provide superior SIH coverages as compared to the previous method. A number of commercially available silica substrates were subjected to an optimum sllanlzatlon procedure, and the resulting materials were further derlvatlzed with 1-octene In the presence of a platinum catalyst. The octyl-bonded phases obtained were shown to have good ligand density as well as enhanced resistance to phase deterioration as compared to conventional octyldlmethylsllyl silicas.

Open‐tubular electrochromatographic characterization of synthetic peptides

“…Bonding of the organic moiety onto the etched inner wall of the capillaries was achieved using the silanization/hydrosilation process adapted for the capillary format [8][9][10][11]. This method permits the attachment of a variety of organic moieties to silica surfaces with the first step being the silanization of the surface by reaction with triethoxysilane (TES) to create a hydride intermediate [8] as shown in Fig. 1.…”

“…This property gives rise to differences in the electroendosmotic flow characteristics as well as peptide selectivity. After the etching process, the modification of the surface with OT-CEC capillaries can be accomplished through a silanization step that creates a hydride layer as an intermediate followed by a hydrosilation reaction to attach the organic moiety [8][9][10]. The complete process for the fabrication of etched chemically modified capillaries can be represented by the schemata (Fig.…”

“…For example, in the case of traditional organosilanization procedures, at least 50% of the silanols remain after the reaction, so significant adsorption of basic compounds can still occur. However, the silanization reaction essentially removes about 95% of the silanols [8] so that after addition of the organic moiety (via hydrosilation) few if any Si-OH groups remain for interaction with basic analytes. Another useful characteristic of etched capillaries is that the electroosmotic flow (EOF) can be either anodic or cathodic [6].…”

A very thin coating for capillary zone electrophoresis of proteins based on a tri(ethylene glycol)‐terminated alkyltrichlorosilane

“…Neutral, hydrophilic polymers, either covalently bound or physically adsorbed, create a thick region of very high viscosity that extends beyond the double layer, effectively eliminating EOF [9]. Covalently bound polymers such as polyacrylamide [8,[10][11][12][13][14] and its derivatives [15][16][17][18] are frequently polymerized in situ, but polymer chains can also be bound to the wall fully formed [19][20][21][22]. A wide variety of neutral hydrophilic polymers have also been used as physically adsorbed coatings for protein separations; these include dextran, hydroxyethylcellulose, hydroxypropylmethylcellulose, poly(vinyl alcohol) [23][24][25], polyethylene oxide [26,27], and acrylamide-based polymers such as poly(acrylamide-co-allyl-b-D-glucopyranoside-coallyl glycidyl ether) (epoxy poly(AG-AA)) [28], epoxy-poly (dimethylacrylamide) (EPDMA) [29], and poly(N-hydroxyethylacrylamide) (PHEA, trade name polyDuramide  ) [30].…”

Fluoroalkylsilane versus Alkylsilane as Hydrophobic Agents for Silica and Silicates

“…Many methods have been proposed to perform the surface modification of fillers, including the sol-gel method (in which organofunctional groups are introduced onto, e.g., silica during its synthesis) [3,4], a method based on the use of water solvents (modification is carried out in a polar environment of water-methanol or water-acetone type) [5], a method based on the use of organic solvents (carried out in anhydrous conditions, anhydrous organic solvent, and dehydrated surface, and the stage of silane hydrolysis being omitted) [6][7][8][9][10], the method of self-organized monolayers (a variation of adsorption from liquid phase) [11][12][13] al., employing a two-stage silanization-alkylation procedure instead of alkylsilylation) [14][15][16], and the gas phase method (fluidal bed) [17][18][19].…”