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Type: Artigo de periódico
Title: Development Of New Urea-functionalized Silica Stationary Phases. Characterization And Chromatographic Performance.
Author: Silva, C R
Jardim, I C
Airoldi, C
Abstract: New urea-functionalized silica stationary phases were prepared by a single-step surface modification through reaction of LiChrosorb Si100 (5 microm particle size) with a homologous series of alkoxysilanes, synthesized in our laboratory, with the general formula (CH3CH2O)3Si(CH2)3NHC(O)NH(CH2)nCH3, where n=4, 6 and 11. The modified silicas were characterized by elemental analysis of carbon and nitrogen, solid-state 29Si- and 13C-cross polarization magic angle spinning nuclear magnetic resonance and nitrogen adsorption isotherms at 77 K. Chromatographic evaluation of the three urea-functionalized silicas in 150x3.9 mm I.D. HPLC columns was carried out by the separation of a test mixture composed of uracil, acetophenone, benzene, toluene and naphthalene, using acetonitrile-water as mobile phase. These new stationary phases, with embedded polar urea groups, are very promising when compared with amide phases prepared by the conventional two-step modification process. A single-step reaction process silica modification is better for obtaining a well-characterized and homogeneous modified surface.
Subject: Chromatography, High Pressure Liquid
Magnetic Resonance Spectroscopy
Silicon Dioxide
Rights: fechado
Identifier DOI: 
Date Issue: 2001
Appears in Collections:Unicamp - Artigos e Outros Documentos

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