نتایج جستجو برای: modified silica

تعداد نتایج: 285512  

2009
A. Mohammad

Various surfactant modified silica layers were used for the chromatography of five different Cephalosporins. The 4% methanolic CTAB impregnated silica layer was useful for the chromatography of Cephalosporins. The acidic buffer solvent systems were used with the 4% methanolic CTAB impregnated silica layers for the separation of different mixtures [A (Cefaclor, Ceftriaxone and Cefadroxil), B (Ce...

Journal: :Journal of chromatographic science 2010
Ye Wang Tao Zhu Kyung Ho Row

A new high-performance liquid chromatography (HPLC) stationary phase was firstly synthesized based on the ionic liquid 2-ethyl-4-methylimidazole chloride. And the performances of the resulting stationary phase were determined by Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), and (13)C nuclear magnetic resonance (NMR) spectroscopy. The retention characteristics of the resu...

2009
Cuiling Ren Jiefang Sun Jinhua Li Xingguo Chen Zhide Hu Desheng Xue

Cadmium telluride (CdTe) and iron oxide nanoparticles doped silica nanospheres were prepared by a multistep method. Iron oxide nanoparticles were first coated with silica and then modified with amino group. Thereafter, CdTe nanoparticles were assembled on the particle surfaces by their strong interaction with amino group. Finally, an outer silica shell was deposited. The final products were cha...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2009
Iuliana E Sendroiu Megan E Warner Robert M Corn

A novel method for preparing gold nanorods that are first coated with a thin silica film and then functionalized with single-stranded DNA (ssDNA) is presented. Coating the nanorods with 3-5 nm of silica improves their solubility and stability. Amine-modified ssDNA is attached to the silica-coated gold nanorods via a reductive amination reaction with an aldehyde trimethoxysilane monolayer. The n...

2004
César Ricardo Silva Carol H. Collins

The authors describe the preparation of a C18 bonded phase using silica chemically modified with tetraisopropyl orthotitanate. The product was reacted with ocadecyltrimethoxysilane to yield a reversed phase. The chromatographic performance of this phase was evaluated for the separation of various test mixtures containing polar, nonpolar, and basic compounds, and its stability at pH 9 and 10 was...

A. Beitollahi, H.R. Rezaie, M.S. Toprak, N. Najmoddin,

The synthesis of mesoporous CuFe2O4 spinel by several nanocasting strategies (i.e., multi-step nanocasting, one step nanocasting, modified solid-liquid), in which copper and iron nitrates are used as precursors and Pluronic P123 as surfactant, is explored. We have also checked the effect of pH, citric acid and sodium citrate in multi-step nanocasting method. The modified solid-liquid method whi...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم پایه دامغان - دانشکده شیمی 1391

اخیراً استفاده از معرف های تثبیت شده بر روی جامدات به دلیل سهولت جداسازی از محیط واکنش گسترش یافته است. در اینجا قصد داریم کاربرد h2so4-silica را به عنوان کاتالیزور اسیدی جامد که از سولفوریک اسید و سیلیکاژل تهیه می شود را برای تهیه نیترو فنول ها و کینولین ها گزارش کنیم. نیترو فنول ها از واکنش بین مشتق های فنول با استرانسیم نیترات در مجاورت h2so4-silica در دمای اتاق و شرایط بدون حلال تهیه شدند. م...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2009
Cristina Fernández-López Cintia Mateo-Mateo Ramón A Alvarez-Puebla Jorge Pérez-Juste Isabel Pastoriza-Santos Luis M Liz-Marzán

Thiol-modified poly(ethylene glycol) (mPEG-SH) has been used to replace standard capping agents from the surfaces of gold nanoparticles with different sizes and shapes. Upon PEG stabilization, the nanoparticles can be transferred into ethanol, where silica can be directly grown on the particle surfaces through the standard Stober process. The obtained silica shells are uniform and homogeneous, ...

2013
Dong Jun Kang Hyeon Hwa Lee Go Un Park Yeol Park

Low-temperature solution processible and solventless silica-epoxy hybrid materials composed of organically modified silica nanoparticles and epoxy monomers were successfully fabricated through simple sol-gel process and solvent evaporation. These silica-epoxy hybrid materials exhibited the homogeneous dispersion without any phase separation, aggregation, and gelation in the solventless environm...

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