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The covalent modification of polymeric particles has been a challenge due to their chemical inertness. Herein we describe a facile and neat method via thiol-ene reaction to immobilize cysteamine/cysteine onto allylmethacrylate-divinylbenzene (AMA-DVB) and ethylvinylbenzene-divinylbenzene (EVB-DVB). The introduced functionalities were verified by elementary analysis and scanning electron microscope coupled with energy dispersive spectroscopy. This modification enabled the further grafting of hyperbranched condensation polymers (HBCPs), which converted the particles into anion exchangers. The anion exchangers demonstrated good separation with carbonate/bicarbonate eluents and hydroxide eluents for suppressed anion exchange chromatography. In the case of a 3-layered anion exchanger, simultaneous separation of nine model anions was achieved by isocratic elution in 17 min with efficiencies up to 16,100 plates m. High stability and dependable durability was exhibited in long-term tests.
is rich in resource. And during its processing, skin is peeled as byproducts. The skin of Alaska Pollock contains lots of collagen or gelatin, promising materials, which can be used in food, cosmetics, biomedical and pharmaceutical industries. Extracting collagen from the dry skin of Alaska Pollock is studied in this study to provide a better basement for fully using this renewable resource. Three kinds of gelatin were extracted by using acid, pepsin-assisted acid and hot water, respectively. The productivity of Acid Soluble Gelatin (ASG), Pepsin Soluble Gelatin (PSG) and hot Water Soluble Gelatin (WSG) were 7.33, 30.89 and 12.67%, respectively. Their UV absorption spectrum were similar and match with the absorption of dilute protein solution. The protein contents of ASG, PSG and WSG were 84-90%, with no significantly difference between them. The characters of SDS-PAGE and the circular dichroism spectrum shown that the PSG is broken into small fragment and has less secondary structure. In conclusion, the hot water extraction is the best way to extract the gelatin from the dry skin of Alaska Pollock.
This work aimed to investigate the process parameters of phytosterol esters (PE) synthesis catalyzed by copper oxide-nano hydroxyapatite (CuO-NHAP) and the crystallization purification technology. CuO-NHAP was prepared. The synthesis of PE catalyzed by CuO-NHAP was performed. After Response Surface Methodology optimization, the optimal process parameters were as follows: reaction temperature, 180 o C; reaction time, 6.3 h; acid-alcohol molar ratio, 1.9; catalyst amount, 1.05%. Under these conditions, the esterification rate of phytosterols was 99.8%. The crystallization purification technology of esterification product was explored. The optimal crystallization conditions were as follows: crystallization solvent, octanoic acid; crystallization temperature, 0 o C; solvent-product molar ratio, 4: 1; crystallization time, 10 h. Under these conditions, the unreacted fatty acids and other impurities were affectively removed, and the PE purity in purification product was 98.2%. These synthesis and crystallization purification technologies of PE are relatively green, safe, efficient and economic, and have the potential to be applied to the industrial preparation of PE product.
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