罗丹明B分子印迹固相萃取小柱的研制及应用

研制一种对罗丹明B具有特异性识别性能的分子印迹固相萃取小柱。用沉淀聚合法制备罗丹明B分子印迹聚合物,通过静态平衡吸附实验及固相萃取实验表征其性能,并对市售辣椒样品中的罗丹明B进行测量。罗丹明B模板聚合物的吸附能力明显优于空白聚合物;印迹固相萃取小柱对罗丹明B标准溶液(0.05 mmol/L)一次性萃取率为98.24%,实际样品测量的回收率为90.0%~95.0%,测定结果的相对标准偏差为0.9%~1.7%(n=3)。罗丹明B分子印迹固相萃取小柱选择性好、萃取率高,可应用于食品、化妆品检测等相关领域。     

氧化环境和比例对改性Hummers法制备GO的影响

以鳞片石墨(GR)为原料,采用改性Hummers法液相氧化方法制备氧化石墨,通过超声剥离的方法剥离出片状的氧化石墨烯(GO),探讨了H₂SO₄环境与H₂SO₄+H₃PO₄混酸环境和KMnO₄与GR的比例对GO制备的影响。采用FTIR、UV、TG、XRD、SEM和XPS等分析手段对制备的GO进行分析。结果表明：GO外貌是呈褶皱片状,在片层上主要有C=O、C-OH、-COOH和C-O-C等官能团,以共价键形式存在石墨层间;通过TG与XPS数据分析表明在H₂SO₄ H₃PO₄混酸环境下制备的GO含氧官能团较多,并且(KMnO₄)与鳞片石墨的最佳比例是1:4。     

Enantioselective synthesis of (1S,4R)-N-(benzylcarbamoyl)-4-aminocyclopent-2-en-1-ol by Candida antarctica lipase B

An efficient biocatalytic process has been developed to obtain optically pure (1S,4R)-N-(benzylcarbamoyl)- 4-aminocyclopent-2-en-1-ol which can be used as the key intermediate of ticagrelor. In this research, several N-(benzylcarbamoyl)-4-aminocyclopent-2-en-1-ol derivatives have been investigated in which Candida antarctica lipase B (CALB) was used to catalyze the asymmetric hydrolysis reaction. As expected, some of these substrates successfully gave (1S,4R)-N-(benzylcarbamoyl)-4-aminocyclopent- 2-en-1-ol in >98% enantiomeric excess (ee) with conversion yields up to 45%.     

Simultaneous determination of naphazoline and pyridoxine in eye drops using excitation–emission matrix fluorescence coupled with second-order calibration method based on alternating trilinear decomposition algorithm

A novel method is developed for the direct determination of naphazoline hydrochloride(NAP) and pyridoxine hydrochloride(VB6) in commercial eye drops. By using excitation–emission matrix(EEM)fluorescence coupled with second-order calibration method based on the alternating trilinear decomposition(ATLD) algorithm, the proposed approach can achieve quantitative analysis successfully even in the presence of unknown and uncalibrated interferences. The method shows good linearity for NAP and VB6 with correlation coefficients greater than 0.99. The results were in good agreement with the labeled contents. To further confirm the feasibility and reliability of the proposed method, the same batch samples were analyzed by multiple reaction monitoring(MRM) based on LC–MS/MS method.T-test demonstrated that there are no significant differences between the prediction results of the two methods. The satisfactory results obtained in this work indicate that the use of the second-order calibration method coupled with the EEM is a promising tool for industrial quality control and pharmaceutical analysis due to its advantages of high sensitivity, low-cost and simple implementation.     

Theoretical study of the structural,elastic, electronic and optical properties of XCaF3 (X = K and Rb)

The PLANE WAVE pseudo-potential method within density functional theory (DFT) has been used to investigate the structural, elastic, electronic and optical properties of XCaF₃ (X = K and Rb) insulating. The studied compounds show a weak resistance to shear deformation compared to the resistance to the unidirectional compression. KCaF₃ and RbCaF₃ are considered ductile. The elastic constants and related parameters were predicted. The stiffness is more important in KCaF₃, whereas, the lateral expansion is more important in RbCaF₃. KCaF₃ and RbCaF₃ have R- Г indirect band gap. The main peaks in the imaginary part of the dielectric function correspond to the transition from the occupied state F₋p to the unoccupied states Ca: s or K, Rb: p. At lower energies, KCaF₃ and RbCaF₃ show the same optical properties. Under pressure effect, the peaks of imaginary part of dielectric function were shifted toward high energy.     

g-C3N4/rGO杂化催化剂的简易合成及其对罗丹明B的光催化降解作用

在空气中直接加热三聚氰胺和氧化石墨烯(GO)的混合物制备了g-C3N4/rGO杂化催化剂.实验结果表明,混合物中的g-C3N4保留了石墨型氮化碳原始的特征结构, g-C3N4和还原的氧化石墨烯(rGO)之间的异质结主要通过π-π作用构筑.当原料中三聚氰胺/GO的质量比是800/1时,所得催化剂对罗丹明B的催化作用最强,其一阶动力学常数是纯g-C3N4的2.6倍.这种强化作用主要是由于rGO促进了光生电子-空穴对的分离.此外, g-C3N4/rGO还表现出显著的pH值敏感特性,催化降解速率随pH的降低而增加.当pH =1.98时,其一阶动力学常数是纯g-C3N4的8.6倍.这是由于酸性条件下质子(H+)消耗掉光生电子,促进了空穴对罗丹明B的氧化作用,其中rGO充当了一个快速的光生电子转移平台.     

Co-Fe/SBA-15与过一硫酸盐联用非均相催化降解水中染料罗丹明B

由于硫酸根自由基(SO4?-)的强氧化性,基于SO4?-的高级氧化技术受到人们的高度关注.采用过渡金属活化过一硫酸盐(PMS)产生SO4?-用以分解有机物,反应体系简单,反应条件温和,且不需要额外的能量供给,因此,成为人们优先选用的方法,其中,采用高效、环境友好的非均相过渡金属催化剂活化PMS处理难降解有机物成为研究热点.本文研究了非均相CoFe/SBA-15-PMS体系对水中难降解染料罗丹明B(RhB)的降解.以SBA-15为载体, Co(NO3)2·6H2O和Fe(NO3)3·9H2O为前驱物,采用一步等体积浸渍法制备了CoFe/SBA-15,通过X射线衍射(XRD)、N2吸附-脱附、扫描电镜(SEM)、能谱(EDS)、透射电镜(TEM)和振动样品磁强计(VSM)等对其进行了表征.考察了焙烧温度、Co与Fe的负载量对CoFe/SBA-15催化性能的影响和该催化剂的重复使用性能,还考察了RhB降解动力学及催化剂CoFe/SBA-15投加量、氧化剂PMS投加量和反应物(RhB和PMS)初始浓度对其性能的影响,探讨了RhB的降解机理.结果表明：对于催化剂CoFe/SBA-15,合成焙烧后在SBA-15上负载的Fe、Co化合物主要是CoFe2O4复合物,它作为催化剂的活性中心负载在SBA-15的孔道内外.制备的焙烧温度对CoFe/SBA-15催化性能几乎无影响,但对Co浸出影响显著.与SBA-15相比,催化剂10Co9.5Fe/SBA-15-700(Co和Fe负载量分别为10 wt%和9.5 wt%,焙烧温度700 oC)的比表面积、孔体积和孔径均减小,分别为506.1 m2/g,0.669 cm3/g和7.4 nm,但仍然保持SBA-15的有序六方介孔结构.该催化剂以棒状体的聚集态存在,聚集体直径大于0.25μm,其磁化强度为8.3 emu/g,因此,可通过外磁铁容易地从水中分离.相比之下,10Co9.5Fe/SBA-15-700具有最佳的催化性能和稳定性,可使RhB的降解率达到96%以上, Co的浸出量小于32.4μg/L.在CoFe/SBA-15和PMS共存下, RhB的降解符合一级动力学方程, RhB降解速率随CoFe/SBA-15和PMS投加量的增加和初始反应物浓度的减小而提高.淬灭实验结果表明,在CoFe/SBA-15, PMS和RhB水溶液体系中,存在的主要活性自由基为SO4?-,它是由CoFe/SBA-15活化PMS产生的,对RhB的降解起决定性的作用. RhB降解过程的UV-vis结果表明, RhB的降解途径主要是蒽环打开, SO4?-优先攻击RhB的有色芳香烃环,然后RhB进一步分解为小分子有机物. CoFe/SBA-15循环使用10次仍能保持高催化活性和稳定性,在每次反应中RhB的降解率均大于84%, Co和Fe的浸出量均分别小于72.1和35μg/L. CoFe/SBA-15作为高效、环境友好的非均相催化剂可有效地活化PMS产生SO4?-降解水中RhB,具有实际应用的潜力.     

Ag_3PO_4/Palygorskite的静电调控合成及可见光催化降解罗丹明B和气相异丙醇

以大比表面的廉价易得的凹凸棒(palygorskite)为载体,借助带电荷界面的静电调控作用,采用吸附-沉积沉淀方法制备磷酸银/凹凸棒(Ag3PO4/palygorskite)复合催化剂.利用X-射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、原子吸收光谱(AAS)、紫外可见漫反射光谱(UV-Vis DRS)等技术系统地表征催化剂.之所以能够制备高分散性的凹凸棒负载的磷酸银催化剂,主要是因为凹凸棒具有较大的比表面积、带负电荷界面以及适宜的磷酸根前驱体.以可见光催化脱色降解罗丹明B和氧化降解异丙醇为探针反应,考察复合材料的催化性能.研究表明,与纯磷酸银相比,磷酸银/凹凸棒催化脱色降解罗丹明B和氧化降解异丙醇速率分别提高了2和2.5倍.     

Nannocystin A: an Elongation Factor 1 Inhibitor from Myxobacteria with Differential Anti‐Cancer Properties

Cultivation of myxobacteria of the Nannocystis genus led to the isolation and structure elucidation of a class of novel cyclic lactone inhibitors of elongation factor 1. Whole genome sequence analysis and annotation enabled identification of the putative biosynthetic cluster and synthesis process. In biological assays the compounds displayed anti‐fungal and cytotoxic activity. Combined genetic and proteomic approaches identified the eukaryotic translation elongation factor 1α (EF‐1α) as the primary target for this compound class. Nannocystin A ( 1 ) displayed differential activity across various cancer cell lines and EEF1A1 expression levels appear to be the main differentiating factor. Biochemical and genetic evidence support an overlapping binding site of 1 with the anti‐cancer compound didemnin B on EF‐1α. This myxobacterial chemotype thus offers an interesting starting point for further investigations of the potential of therapeutics targeting elongation factor 1.