Chiral separation of raltitrexed by cyclodextrin-modified micellar electrokinetic chromatography

A rapid and effective method was developed for the chiral separation of raltitrexed (RD) enantiomers by carboxymethyl-beta-cyclodextrin (CM-β-CD)-modified micellar electrokinetic chromatography (MEKC). Optimization of conditions including the type and concentration of the chiral selector, concentration of sodium dodecyl sulfate (SDS), pH and concentration of the background electrolyte (BGE), capillary temperature, and applied voltage was investigated. The enantiomers of raltitrexed could be separated with satisfactory resolution and linear response by using 75 mM Tris-phosphate at pH 8.0 containing 30 mM SDS and 8 mM CM-β-CD as buffer system. Furthermore, the usefulness of this method was demonstrated in a purity test of a real synthetic drug sample. Figure Chiral separation of raltitrexed by CM-β-CD MEKC was optimized and applied to test the purity of a synthetic drug sample     

聚甲基丙烯酸甲酯/苯乙烯-丙烯腈无规共聚物薄膜表面原位原子力显微镜相图

采用原位原子力显微镜在线跟踪方法,研究了聚甲基丙烯酸甲酯/苯乙烯 丙烯腈无规共聚物共混体系表面相分离行为,得到了具有下临界共溶温度（临界温度约为175 ℃）原位相图。 与文献报道的用离位方法所得结果的主要差别是原位的临界相分离温度稍有提高,以及离位结果中存在的组成对称性。 这些差别主要来源于离位和原位实验方法上的差别,薄膜厚度减小导致的相容性,热力学历史的变化以及基底效应的加剧。     

十三氟辛基修饰的疏水有机-无机杂化二氧化硅膜孔结构、氢气分离及水热稳定性

采用1,2-双(三乙氧基硅基)乙烷(BTESE)和十三氟辛基三乙氧基硅烷(PFOTES)为前驱体,在酸性条件下通过溶胶-凝胶法制备了十三氟辛基修饰的有机-无机杂化SiO2膜材料。利用接触角测量、红外光谱、动态光散射和N2吸附等测试技术分别对膜材料的疏水性、溶胶粒径和孔结构进行表征,并深入研究有支撑膜材料的氢气渗透、分离性能以及长期水热稳定性。结果表明,十三氟辛基修饰后的膜材料由亲水性变成了疏水性,当nPFOTES/nBTESE=0.6时膜材料对水的接触角达到(110.4±0.4)°,膜材料还保持微孔结构,孔径分布在0.5~0.8 nm。氢气在修饰后的膜材料中的输运遵循微孔扩散机理,在300℃时,氢气的渗透率达到8.5×10-7mol·m-2·s-1·Pa-1,H2/CO2,H2/CO和H2/SF6的理想分离系数分别为5.49,5.90和18.36,均高于相应的Knudsen扩散分离因子。在250℃且水蒸气物质的量分数为5%水热环境下陈化250 h,氢气渗透率和H2/CO2的理想分离系数基本保持不变,膜材料具有良好的水热稳定性。     

气体扩散耦合顺序注射光度分析法测定葡萄酒中的二氧化硫*

依据在微碱性条件下,亚硫酸根离子可与孔雀绿溶液发生加成反应并使其褪色的原理,建立了气体扩散耦合顺序注射分光光度法测定葡萄酒中二氧化硫的新方法。当接收液流速为1.2mL/min和4.2mL/min时,方法的线性响应范围分别为1.0-5.0μg/mL和5.0-50.0μg/mL,方法的检出限为0.33μg/mL,相对标准偏差（RSD）≤0.43%,对葡萄酒样中二氧化硫测定的加标回收率为98.7%-104.7%。     

金属有机骨架材料/聚酰亚胺混合基质膜的制备及气体分离性能

合成了3种不同结构、 粒径和气体吸附性能的金属有机骨架材料(MOFs): 微米级Cu₃(BTC)₂、 亚微米级ZIF-8和S-Cu₃(BTC)₂. 氮气吸附等温线分析结果表明, ZIF-8和Cu₃(BTC)₂具有较大比表面积(1653和1439 m²/g), S-Cu₃(BTC)₂的比表面积为171.4 m²/g. 用共混法将MOFs直接引入聚酰亚胺中制备了MOFs/聚酰亚胺混合基质膜(MMMs). X射线衍射(XRD)和全反射红外光谱(FTIR-ATR)分析结果表明, MOFs在混合基质膜中保持物理和化学稳定. 气体渗透测试结果表明, MOFs的加入使膜的气体渗透分离性能明显提高, S-Cu₃(BTC)₂使渗透系数增加了1.75倍; ZIF-8和Cu₃(BTC)₂使渗透系数增加了3倍左右; 同时, 膜的气体分离系数变化很小.     

磷酸修饰对纳米Fe2O3热稳定性及光催化性能的影响

通过溶液浸渍蒸干过程实现了磷酸对Fe₂O₃纳米粒子的表面修饰, 研究了磷酸修饰对纳米Fe₂O₃的热稳定性及光催化活性的影响. 结果表明, 磷酸修饰显著提高了Fe₂O₃的热稳定性, 主要归因于磷酸修饰在样品表面抑制了粒子之间的团聚生长. 同时, 在光催化降解气相乙醛和液相苯酚的测试中, 磷酸修饰后热处理温度为600 ℃的样品表现出了最佳的可见光催化性能, 这主要归因于该样品具有高晶化度、 小粒子尺寸及大比表面积, 并且适量的修饰有利于其光催化性能的提高.     

金红石相TiO_2纳米棒的氢化处理及其光催化活性

以钛酸四丁酯为钛源,通过盐酸调制的水热法制备出了具有棒状结构的金红石相纳米TiO2,并进一步进行高温氢化处理.采用X射线衍射(XRD),透射电镜(TEM),紫外-可见-近红外漫反射(UV-Vis-NIR DRS),电子顺磁共振(EPR)和表面光伏(SPS)等测试手段对样品进行表征,以气相乙醛和液相苯酚为目标污染物考察催化剂的光催化活性.结果表明:随着高温氢化处理时间的延长,TiO2样品的可见光吸收逐渐增强,其颜色逐渐由白色转变成灰色,这主要与引入的Ti3+/氧空位缺陷有关.表面光电压谱和羟基自由基测试表明,适当时间的氢化处理有利于光生电荷的分离.在光催化氧化降解气相乙醛和液相苯酚过程中,经适当时间氢化处理的样品表现出高的可见光催化活性.并且可见光催化活性的规律与紫外光下的是一致的.这是因为氢化处理后在导带底下方引入了缺陷能级,拓展了可见光响应.过度的氢化处理会在TiO2导带下方引入较低的缺陷能级,使光生电荷的复合加剧,导致光催化活性降低.     

A hierarchical porous carbon membrane from polyacrylonitrile/polyvinylpyrrolidone blending membranes:Preparation,characterization and electrochemical capacitive performance

Novel hierarchical porous carbon membranes were fabricated through a simple carbonization procedure of well-defined blending polymer membrane precursors containing the source of carbon polyacrylonitrile （PAN） and an additive of polyvinylpyrrolidone （PVP）, which was prepared using phase inversion method. The as-fabricated materials were further used as the active electrode materials for supercapacitors. The effects of PVP concentration in the casting solution on structure feature and electrochemical capacitive performance of the as-prepared carbon membranes were also studied in detail. As the electrode material for supercapacitor, a high specific capacitance of 278.0 F/g could be attained at a current of 5 mA/cm2 and about 92.90% capacity retention could be maintained after 2000 charge/discharge cycles in 2 mol/L KOH solution with a PVP concentration of 0.3 wt% in the casting solution. The facile hierarchical pore structure preparation method and the good electrochemical capacitive performance make the prepared carbon membrane particularly promising for use in supercapacitor.     

还原氧化石墨烯基三聚氰胺海绵的制备与吸附性能

以天然石墨为原料,用Hummers法和超声剥离法制备了氧化石墨烯(GO).将氧化石墨烯浸渍,涂覆于三聚氰胺海绵表面,在线还原制得还原氧化石墨烯基三聚氰胺海绵(RGOME).通过扫描电子显微镜(SEM)、傅里叶变换红外光谱(FTIR)仪及光学接触角测定仪等分析了RGOME的结构,考察了RGOME对多种油品的吸附性能,并对其油水选择吸附性能和循环使用性能进行了研究.结果表明,RGOME具有疏水超亲油性,对油品的吸附量达到56~127 g/g,可用Bangham方程描述RGOME对甲苯和煤油的吸附动力学过程;在选择吸附过程中,油品浓度急剧降低,吸附量不断升高,分离效率达到74.49%,可较好地实现油水分离;吸附油品的RGOME经脱附可多次循环使用.     

Design criteria for tetradentate phenanthroline-derived heterocyclic ligands to separate Am(Ⅲ) from Eu(Ⅲ)

To design novel phenanthroline-derived soft ligands for selectively separating minor actinides from lanthanides, four tetradentate phenanthroline-derived heterocyclic ligands(BTPhen, BPyPhen, BPzPhen, and BBizPhen) were constructed and their complexation behaviors with Am(ⅡI) and Eu(ⅡI) were systematically investigated by density functional theory(DFT) coupled with relativistic small-core pseudopotential. In all the 1:1-type species, the metal ion is in the center of the cavity and coordinates with two nitrogen atoms(N1 and N1′) of the phenanthroline skeleton and the other two nitrogen atoms(N2 and N2′) of the auxiliary groups. The bond lengths of Am–N are comparable to or even shorter than those of Eu–N bonds because the ionic radii of Am(ⅡI) are larger than those of Eu(ⅡI). Additionally, the negative ΔΔGAm/Eu value for the reaction of [M(H2O)4-(NO3)3] + L → ML(NO3)3 + 4H2 O indicates that the complexation reaction of Am(ⅡI) is more energetically favorable than that of Eu(ⅡI); this can be considered as an important design criterion to screen phenanthroline-derived ligands for MA(ⅡI) extraction. According to this criterion, the selectivity of tetradentate phenanthroline-derived ligands for separating Am(ⅡI) over Eu(ⅡI) follows the order of BTPhen BBizPhen BPyPhen BPzPhen.