2 research outputs found

    Small-Angle Neutron Scattering Study of Cyclic Poly(ethylene glycol) Adsorption on Colloidal Particles

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    The adsorptions of cyclic PEG and linear PEG on colloidal silica particles were compared. Their adsorption volume fraction profiles were generated through model fitting of small-angle neutron scattering data from the adsorbed polymer layers. The two important parameters to describe adsorbed polymer layers were discussed in detail. It was found that the adsorption amounts of cyclic PEGs increased with molecular weight but were generally higher than their linear counterparts. However, the root-mean-square layer thickness, δ<sub>rms</sub>, of adsorbed cyclic PEGs was found to decrease with molecular weight, opposing adsorbed linear PEGs and the theoretic prediction based on SF model. This disagreement was ascribed to the topological restriction of cyclic polymer at low molecular weight. An illustrated structural evolution with molecular weight for adsorbed polymer at interface was tentatively proposed based on the observations of this study

    Combination of Running-Buffer-Mediated Extraction and Polyamidoamine-Dendrimer-Assisted Capillary Electrophoresis for Rapid and Sensitive Determination of Free Fatty Acids in Edible Oils

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    A method was developed for determining free fatty acids in edible plant oils by incorporation of running-buffer-mediated liquid–liquid extraction and polyamidoamine-dendrimer-assisted capillary electrophoresis–capacitively coupled contactless conductivity detection. The recoveries for the extraction were in the range of 90.1% and 110.3%. Addition of dendrimer to the running buffer improved the separation of fatty acids. Under the optimized buffer conditions, i.e., 3 mM pelargonic acid, 39 mM tris­(hydroxymethyl)­aminomethane, 30 mM polyoxyethylene 23 lauryl ether, 35% acetonitrile, 15% 2-propanol, 2.5% 1-octanol, and 300 μM polyamidoamine generation 2 at apparent pH 8.53, the 10 model fatty acids were separated in 18 min with detection limits ranging from 0.46 to 3.28 μM. The successful determination of fatty acids in real samples suggests that the method is simple, cost-effective, and easy to operate and is suitable for scanning free fatty acid in edible plant oils
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