Aminopolysiloxane gels: production and properties

Zhmud, Boris; Sonnefeld, J.

doi:10.1016/0022-3093(95)00497-1

Cited by 77 publications

(90 citation statements)

References 19 publications

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“…Also, it may be observed that the condensation of aminopropyl with salicylaldehyde, giving the Schiff base, lowers the catalytic effect of free aminopropyl in the silica hydrolysis. 34 These results confirm the relative stability of the controlled-pore silica glass as a support for N-propylsalicylaldimine. It also indicates the possibility of studying the effect of the time of stirring on the separation of the investigated metal ions by using SCPSG without any noticeable loss of the solid phase due to hydrolysis (weight loss as SiO2 after 60 min stirring at pH 9 = 0.59%).…”

Section: Calibrationsupporting

confidence: 71%

Controlled-pore Silica Glass Modified with N-Propylsalicylaldimine for the Separation and Preconcentration of Trace Al(III), Ag(I) and Hg(II) in Water Samples

Mostafa

Hassanien²,

Abou‐El‐Sherbini

et al. 2003

ANAL. SCI.

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Controlled-pore silica glass modified with N-propylsalicylaldimine (SCPSG) has been investigated as a surface-active matrix for the separation of some metal ions. The porous silica glass base was confirmed to have better stability towards hydrolysis in aqueous solution buffered at pH = 9 in comparison to silica gel, which showed twice the surface area of controlled-pore silica glass. The different analytical parameters affecting the batch mode separation and preconcentration of trace Al(III), Ag(I) and Hg(II) in environmental samples using SCPSG, prior to their determination using inductively coupled plasma mass spectrometry (ICP-MS), were studied. The optimum conditions are pH 9.0 ± 0.1, time of stirring 30 min and the eluent concentration 0.5 mol dm -3 HNO3. The ion-exchange capacity of SCPSG with respect to Al(III), Ag(I) and Hg(II) was 0.27, 0.18 and 0.23 mmol g -1 , respectively. The recovery values for the metal ions were 96.8 ± 0.86, 98.1 ± 0.60 and 96.2 ± 1.06%, and the analytical detection limits were 26.1, 1.49 and 0.44 pg cm -3 , respectively, for a preconcentration factor of 100. The method has been applied to the determination of the investigated metal ions in natural water samples as well as certified and reported samples and the results were found to be accurate.

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Section: Calibrationsupporting

confidence: 71%

Controlled-pore Silica Glass Modified with N-Propylsalicylaldimine for the Separation and Preconcentration of Trace Al(III), Ag(I) and Hg(II) in Water Samples

Mostafa

Hassanien²,

Abou‐El‐Sherbini

et al. 2003

ANAL. SCI.

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“…The presence of APTES favours the formation of cyclic intermediates, reported in Scheme 2, that probably provides an energetically favourable reaction path. [16] Cyclic intermediates formed during the hydrolysis/condensation reactions of an APTES-TEOS mixture speed up the hydrolysis and allow us to obtain the gel carriers without using acid catalysis. We have prepared samples with increasing APTES amount in the gel composition, as reported in Table 1.…”

Section: Aptes/teos Samplesmentioning

confidence: 99%

“…In the present study, the silica structure is modified with the introduction of hydrophilic groups by using the (3-aminopropyl) triethoxysilane (APTES) as precursor in a sol-gel process. APTES is employed in many fields of the modern chemistry and technology for chemical modification of various oxide surfaces and for surface coatings; [16] moreover, in this last decade several reports have been published on its use as modifier agent of porous silica employed as carriers for encapsulation and delivery of pharmaceutical drugs. [14,17] However, to the best of our knowledge, only a few studies [18] have been reported, up to now, on hybrid amine-silica carriers prepared by sol-gel methods used for the sustained release of drugs.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Organic–Inorganic Silica Gel Carriers with Controlled Drug‐Delivery Properties

Contessotto

Ghedini

Pinna

et al. 2009

Chemistry A European J

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Pure and modified silica materials were synthesised by a sol–gel process and used as carrier for the controlled release of ibuprofen, selected as model drug. A one‐step synthesis was optimised for the preparation of various silica–drug composites by using tetraethoxysilane and 3‐aminopropyltriethoxysilane as precursors at different molar ratios. The presence of aminopropyl groups on the silica surface influences the drug‐delivery rate leading to a high degree the desorption process controlled.

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“…2). Use of APS samples under their protonated form was preferred over the unprotonated amine function (even if Hg II is liable to form immobilized complexes on silica materials grafted with amine groups [8]), because APS are much more stable in acidic medium than at higher pH where base-catalyzed solubilization of the material is known to occur [53,54].…”

Section: Access Rate To the Binding Sites ± Influence Of Speciationmentioning

confidence: 99%

Grafted Silicas in Electroanalysis: Amorphous Versus Ordered Mesoporous Materials

et al. 2003

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This work reports the enhanced response of electrodes modified with ordered mesoporous silica-based materials, as compared to corresponding amorphous materials, in case of open-circuit accumulation and voltammetric detection of a target analyte. Several porous silica samples grafted with either thiol or ammonium groups, displaying high surface areas with various structural characteristics and different pore sizes, have been examined with respect to their ability to concentrate Hg II species. Better accessibility to the binding sites and faster diffusion processes in the interior of grafted silicas have been observed for the ordered samples prepared by micelle-templating because they contain channels of regular size, which are less tortuous than the irregular pore systems in amorphous materials. When applied in electrochemical detection of Hg II after preconcentration, the ordered solids gave rise to voltammetric signals higher by more than one order of magnitude in comparison to the amorphous organically-modified silicas. This rather new class of materials, which can be easily produced as ordered organic-inorganic hybrids, is expected to improve the performance of silica-modified electrodes in various fields of electroanalysis.

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Aminopolysiloxane gels: production and properties

Cited by 77 publications

References 19 publications

Controlled-pore Silica Glass Modified with N-Propylsalicylaldimine for the Separation and Preconcentration of Trace Al(III), Ag(I) and Hg(II) in Water Samples

Controlled-pore Silica Glass Modified with N-Propylsalicylaldimine for the Separation and Preconcentration of Trace Al(III), Ag(I) and Hg(II) in Water Samples

Hybrid Organic–Inorganic Silica Gel Carriers with Controlled Drug‐Delivery Properties

Grafted Silicas in Electroanalysis: Amorphous Versus Ordered Mesoporous Materials

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