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Novel 3‐hydroxypropyl‐bonded phase by direct hydrosilylation of allyl alcohol on amorphous hydride silica
Author(s) -
Gómez Jorge E.,
Navarro Fabián H.,
Sandoval Junior E.
Publication year - 2014
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201400216
Subject(s) - hydrosilylation , hydride , phase (matter) , amorphous solid , alcohol , allyl alcohol , materials science , chemistry , chemical engineering , organic chemistry , polymer chemistry , catalysis , engineering , hydrogen
A novel 3‐hydroxypropyl (propanol)‐bonded silica phase has been prepared by hydrosilylation of allyl alcohol on a hydride silica intermediate, in the presence of platinum (0)‐divinyltetramethyldisiloxane ( K arstedt's catalyst). The regio‐selectivity of this synthetic approach had been correctly predicted by previous reports involving octakis(dimethylsiloxy)octasilsesquioxane ( Q 8 M 8 H ) and hydrogen silsesquioxane ( T 8 H 8 ), as molecular analogs of hydride amorphous silica. Thus, C ‐silylation predominated (∼94%) over O ‐silylation, and high surface coverages of propanol groups (5 ± 1 μmol/m 2 ) were typically obtained in this work. The propanol‐bonded phase was characterized by spectroscopic (infrared ( IR ) and solid‐state NMR on silica microparticles), contact angle (on fused‐silica wafers) and CE (on fused‐silica tubes) techniques. CE studies of the migration behavior of pyridine, caffeine, Tris(2,2′‐bipyridine)Ru(II) chloride and lysozyme on propanol‐modified capillaries were carried out. The adsorption properties of these select silanol‐sensitive solutes were compared to those on the unmodified and hydride‐modified tubes. It was found that hydrolysis of the S i H species underlying the immobilized propanol moieties leads mainly to strong ion‐exchange‐based interactions with the basic solutes at p H 4, particularly with lysozyme. Interestingly, and in agreement with water contact angle and electroosmotic mobility figures, the silanol–probe interactions on the buffer‐exposed (hydrolyzed) hydride surface are quite different from those of the original unmodified tube.