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81.
Wei Li Zhuang‐Fei Jiang Ling Tan Shu‐Xian Wang Chong‐Zhi Wang Jia‐Wei Zhang Lian‐Di Zhou Qi‐Hui Zhang Chun‐Su Yuan 《Journal of separation science》2020,43(6):1173-1182
Curcumin widely exists in food, and rapid selective and accurate detection of curcumin have great significance in chemical industry. In this experiment, a new magnetic biocompatibility molecularly imprinted polymer was prepared with nontoxic and biocompatible Zein to adsorb curcumin selectively. The polymer has high biocompatibility, good adsorption capacity, and specific adsorption for curcumin. Combined with portable electrochemical workstations, the polymer can be used to detect curcumin rapidly and cost‐effectively. Using curcumin as a template and Zein as the crosslinking agent, the polymers were synthesized on the surface of Fe3O4 particles for solid phase extraction. The experimental results showed that the polymer reached large adsorption capacity (32.12 mg/g) with fast kinetics (20 min). The adsorption characteristic of the polymer followed the Langmuir isotherm and pseudo‐second‐order kinetic models. Hexacyanoferrate was used as electrochemical probe to generate signals, and the linear range was 5–200 µg/mL for measuring curcumin. The experimental analysis showed that the polymer was an ideal material for selective accumulation of curcumin from complex samples. This approach has been successfully applied to the determination of curcumin in food samples with electrochemical detection, indicating that this is a feasible and practical technique. 相似文献
82.
WO3/ZrO2固体酸催化苯与1-己烯烷基化反应 总被引:3,自引:0,他引:3
用浸渍法制备了WO3/ZrO2及碱金属K或碱土金属Sr掺杂改性的WO3/ZrO2固体酸催化剂. 采用X射线衍射、 N2吸附、 NH3程序升温脱附和吸附吡啶的红外光谱等技术表征了K或Sr对WO3/ZrO2催化剂结构和表面酸性质的影响. 研究了WO3/ZrO2及K或Sr掺杂改性的WO3/ZrO2固体酸对苯与1-己烯烷基化反应的催化性能. 考察了催化剂制备条件和反应条件对催化剂活性的影响以及催化剂的重复使用性. 结果表明,引入K或Sr可调变WO3/ZrO2固体酸中的ZrO2晶相和固体酸的酸强度、酸量以及Lewis酸中心与Brnsted酸中心的比值. 适量K或Sr掺杂改性可提高WO3/ZrO2催化剂对苯与1-己烯烷基化反应的催化活性和稳定性,在常压和80 ℃的温和条件下,反应10 min后, 1-己烯的转化率可达99%, 单烷基选择性为100%. 该催化剂可多次重复使用,催化活性稳定. 相似文献
83.
Fei Zhao Xiaosong Zhai Xuemei Liu Meng Lian Guoting Liang Jingxiang Cui Haizhou Dong Wentao Wang 《Molecules (Basel, Switzerland)》2022,27(1)
The purpose of this paper was to investigate the effect of high-intensity ultrasonication (HIU) pretreatment before enzymolysis on structural conformations of walnut protein isolate (WPI) and antioxidant activity of its hydrolysates. Aqueous WPI suspensions were subjected to ultrasonic processing at different power levels (600–2000 W) and times (5–30 min), and then changes in the particle size, zeta (ζ) potential, and structure of WPI were investigated, and antioxidant activity of its hydrolysates was determined. The particle size of the particles of aqueous WPI suspensions was decreased after ultrasound, indicating that sonication destroyed protein aggregates. The ζ-potential values of a protein solution significantly changed after sonication, demonstrating that the original dense structure of the protein was destroyed. Fourier transform infrared spectroscopy indicated a change in the secondary structure of WPI after sonication, with a decrease in β-turn and an increase in α-helix, β-sheet, and random coil content. Two absorption peaks of WPI were generated, and the fluorescence emission intensity of the proteins decreased after ultrasonic treatment, indicating that the changes in protein tertiary structure occurred. Moreover, the degree of hydrolysis and the antioxidant activity of the WPI hydrolysates increased after sonication. These results suggest that HIU pretreatment is a potential tool for improving the functional properties of walnut proteins. 相似文献
84.
Leyu Xin Limin Guo Salamet Edirs Zepeng Zhang Chenyang Cai Yongxing Yang Yali Lian Haiyan Yang 《Molecules (Basel, Switzerland)》2022,27(7)
Safflower seed oil (SSO) is considered to be an excellent edible oil since it contains abundant essential unsaturated fatty acids and lipid concomitants. However, the traditional alkali-refined deacidification process of SSO results in a serious loss of bioactive components of the oil and also yields massive amounts of wastewater. In this study, SSO was first extracted by ultrasonic-assisted ethanol extraction (UAEE), and the extraction process was optimized using random centroid optimization. By exploring the effects of ethanol concentration, solid–liquid ratio, ultrasonic time, and the number of deacidification times, the optimum conditions for the deacidification of safflower seed oil were obtained as follows: ethanol concentration 100%, solid–liquid ratio 1:4, ultrasonic time 29 min, and number of deacidification cycles (×2). The deacidification rate was 97.13% ± 0.70%, better than alkali-refining (72.16% ± 0.13%). The values of acid, peroxide, anisidine and total oxidation of UAEE-deacidified SSO were significantly lower than those of alkali-deacidified SSO (p < 0.05). The contents of the main lipid concomitants such as tocopherols, polyphenols, and phytosterols in UAEE-decidified SSO were significantly higher than those of the latter (p < 0.05). For instance, the DPPH radical scavenging capacity of UAEE-processed SSO was significantly higher than that of alkali refining (p < 0.05). The Pearson bivariate correlation analysis before and after the deacidification process demonstrated that the three main lipid concomitants in SSO were negatively correlated with the index of peroxide, anisidine, and total oxidation values. The purpose of this study was to provide an alternative method for the deacidification of SSO that can effectively remove free fatty acids while maintaining the nutritional characteristics, physicochemical properties, and antioxidant capacity of SSO. 相似文献
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88.
高度分散的Pt/TiO2的制备及光催化活性 总被引:7,自引:2,他引:7
用柠檬酸作为空穴捕获剂和分散剂,在温和条件下用光催化还原法将3nm金属铂沉积在7nm的锐钛矿相及介孔二氧化钛纳米晶表面,TEM观察显示铂的负载量为w=1.0%时,多数二氧化钛纳米晶表面沉积了岛状的铂团簇,XPS和电子衍射结果表明铂以游离态存在.负载w=1.0%~2.0%铂的TiO2在苯酚光氧化反应中活性显著提高,Pt/TiO2在氨气中经550℃氮化,可制得氮掺杂的Pt/TiO2可见光光催化剂,氮化过程中铂团簇没有烧结和显著长大。 相似文献
89.
聚N,N-双水杨醛乙二胺合钴修饰超微电极的制备及其在一氧化氮测定中应用的研究 总被引:6,自引:0,他引:6
通过电化学聚合法制备了聚N,N-双水杨醛乙二胺合钴[polyCo(Salen)]修饰超微电极,研究了该修饰电极的电催化性质及其在一氧化氮(NO)测定中的应用.实验结果表明,polyCo(Salen)修饰超微电极对NO的测定有高的灵敏度,NO的浓度在2.0×10-8~2.8×10-6mol/L范围内,电流与浓度呈良好的线性关系,线性相关系数为0.9998,检出限为1.0×10-8mol/L;该电极进一步修饰Nafion后,生物体中常见的物质如抗坏血酸、儿茶酚胺类神经递质的代谢物、NO的氧化产物NO-2等不干扰测定.本传感器可以满足NO在体分析的需要. 相似文献
90.
A new compound of 4,4'-diamino-N,N'-diethyl bisbenzenesulfamide (C18H26N4O4S2,Fw = 426.55) has been synthesized and its structure was determined by X-ray crystallography method. The crystal belongs to the monoclinic system, space group P21/c with a = 10.0623(9), b =13.6759(13), c =15.5309(14) (A),β = 100.482(2)°, V= 2101.6(3)(A)3, Dc = 1.348 g/cm3, F(000) = 904,μ = 0.285 mm-1, Z = 4, the final R = 0.0512 and wR = 0.1363 for 3485 observed reflections with I >2σ(Ⅰ). The structure of the title compound is pseudo secondary axisymmetric, and the two sulfamide-groups show distorted tetrahedral configurations. 相似文献