Aroma Retention in Sol−Gel-Made Silica Particles

Veith, Susanne R.; Pratsinis, Sotiris E.; Perren, Matthias

doi:10.1021/jf049356a

Cited by 17 publications

(13 citation statements)

References 27 publications

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“…These studies gave some evidence that the porosity of the inorganic matrix has a strong influnece on both the retaining ability of the silica matrix and the release kinetics of the template. 39,40 Correlation between Release and Rebinding Experiments Sellergren et al have used an in situ release test for the screening and selection of potential MIP candidates in combinatorial synthesis. 41,42 In this work, 1 mL of porogen was added to polymerized mini-MIPs (50 mg each), and the concentration of released template in the supernatant was measured after few hours of equilibration.…”

Section: Effect Of Mip Morphology On the Release Profilementioning

confidence: 99%

Influence of Polymer Morphology on the Capacity of Molecularly Imprinted Resins to Release or to Retain their Template

et al. 2009

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This paper deals with the specific ability of molecularly imprinted polymers (MIPs) to release and/or to retain their template. MIPs for caffeine with various MIP:porogen volume ratios were prepared by a non-covalent route. Formation of a prepolymerization complex between the template and the functional monomer was confirmed by nuclear magnetic resonance and computer simulation. The MIP monoliths were successively grinded, sieved, and dried under vacuum. The morphology of the imprinted particles was investigated by scanning electron microscopy, swelling experiments and nitrogen adsorption. Typical release patterns of as-synthesised MIP particles in solvents can be decomposed in three fractions: initial release ( 0 ), slow release over several hours (Á Release ), permanent retention/encapsulation within the MIP (Á Reservoir ). The effect of MIP:porogen volume ratio (related to the MIP porosity) on the releasing/retaining profiles of the materials has been investigated. Finally, the results were critically compared with the available literature and the applicability of MIP reservoirs is briefly discussed.KEY WORDS: Molecular Imprinting / Polymer Morphology / Controlled Release / Polymer Reservoir / Self-Assembly / Molecular imprinting is an emerging technology, which allows the molecular design of polymeric materials containing highly specific receptor sites with an affinity for target compounds.1-3 Formation of a self-assembled pre-polymerization complex between a template molecule and functional monomers, followed by polymerization with a cross-linker in a porogenic solvent and the subsequent extraction of the template, produces a molecularly imprinted polymer (MIP) possessing specifically sized and shaped cavities capable of molecular recognition. 4,5 MIPs are generally highly crosslinked thermosets, and therefore porosity is a necessary feature of their morphology to allow permeability and transport of templates molecules to the bulk polymer phase.To date, a number of promising applications have been proposed for MIPs. For instance, imprinted polymers are used in chromatography as the stationary phase for separation and isolation of racemates.6,7 A related area is solid-phase extraction, where imprinted polymers are employed as a selective sorbent to concentrate the molecule of interest.8 MIPs are also used in immunoassays-type analyses as synthetic antibody 9 and in catalysis as enzyme mimics. 10,11 In the emerging field of biosensors, MIPs demonstrate a potential as the recognition element, although their performance and selectivity in aqueous systems is still a limiting factor. 12,13The application of desorption properties of MIPs is a relatively new area.14,15 Chromatographic data have shown that the MIP-template dissociation kinetics can be controlled by varying the local environment (MIP composition, solvent. . .). Therefore, it seems feasible that MIPs could form highly specific rate limiting reservoirs releasing active compounds at well-defined rates. Early studies delivered promising results and showe...

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Section: Effect Of Mip Morphology On the Release Profilementioning

confidence: 99%

Influence of Polymer Morphology on the Capacity of Molecularly Imprinted Resins to Release or to Retain their Template

et al. 2009

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“…Considering that our materials are functionalized with cation exchange groups, interaction of esters and acids by these mechanisms is not likely to occur given the pH of the wine. However, a retention effect due to hydrogen bonding with silanol groups and/or an acid catalytic effect of the sulfonic groups on the hydrolysis reaction of the esters are more probable 27,28 . Therefore, a chemical and sensory evaluation (mainly focusing on aroma) of the wines after a time in storage must be carried out in order to evaluate the final effect of the treatments.…”

Section: Resultsmentioning

confidence: 99%

Removal of biogenic amines from wines by chemisorption on functionalized silica and effects on other wine components

Rodríguez‐Bencomo

Rigou

Mattivi

et al. 2020

Sci Rep

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The effectiveness of several functionalized silica materials (cation-exchange materials) for the removal of biogenic amines from wines, and the effects on other wine components and organoleptic characteristics were evaluated. Results have shown that mesoporous silica material bi-functionalized with phosphonic and sulfonic acids allowed the removal of histamine, putrescine, cadaverine, spermine and spermidine from wines, although the dose must be adapted for each wine according to the removal requirements and wine characteristics. A plus of the adsorbent developed is that it can be recovered and re-used for at least 3 treatments. Immediately following the treatments, a decrease in the levels of linear ethyl esters (ethyl hexanoate, ethyl octanoate and ethyl decanoate) was observed, although these levels were re-equilibrated after several days reducing this undesired side effect. A slight, but perceptible, effect on wine color was observed, probably due to the slight decrease in the pH of the wine produced by the treatments. On the basis of the sensory analysis that focused only on the aroma of the wines, the proposed technique would be more adequate for wines aged in barrels than for young wines.

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“…Given the hydrophilic nature of glycerol, the interactions of the hydroxyl functions with the silanol groups of silica are certainly stronger—in full agreement with the well-known retention of alcohols entrapped in silica xerogels. 13 …”

Section: Resultsmentioning

confidence: 99%

Sol‐Gel Microspheres Doped with Glycerol: A Structural Insight in Light of Forthcoming Applications in the Polyurethane Foam Industry

et al. 2015

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Porous silica-based microspheres encapsulating aqueous glycerol can be potential curing agents for one-component foams (OCFs). Such agents have the advantage of an enhanced sustainability profile on top of being environmentally friendly materials. A synthetically convenient and scalable sol-gel process was used to make silica and organosilica microspheres doped with aqueous glycerol. These methyl-modified silica microspheres, named “GreenCaps”, exhibit remarkable physical and chemical stability. The microspheres were characterized by scanning electron microscopy, transmission electron microscopy at reduced pressure, and cryogenic nitrogen adsorption—desorption analysis. The structure of the materials was also analyzed at the molecular level by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. As expected, the degree of methylation affects the degree of encapsulation and pore structure. Microspheres similarly methylated, however, can differ considerably in surface area and pore size due to the templating effect of glycerol on the organosilica structure. The results of the structure analysis reveal that glycerol is efficiently encapsulated, acts as a template, barely leaches over time, but is released by depressurization. A proper application of these microspheres can later on enhance both the environmental and health profile, as well as the technical performance (curing speed, foam quality, and froth thixotropy) of spray polyurethane foams.

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Aroma Retention in Sol−Gel-Made Silica Particles

Cited by 17 publications

References 27 publications

Influence of Polymer Morphology on the Capacity of Molecularly Imprinted Resins to Release or to Retain their Template

Influence of Polymer Morphology on the Capacity of Molecularly Imprinted Resins to Release or to Retain their Template

Removal of biogenic amines from wines by chemisorption on functionalized silica and effects on other wine components

Sol‐Gel Microspheres Doped with Glycerol: A Structural Insight in Light of Forthcoming Applications in the Polyurethane Foam Industry

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