基于石墨化炭黑预涂覆技术的色谱柱制备和性能评价

采用石墨化炭黑(GCB)预涂覆技术对白酒分析专用色谱柱(LZP-930)的制备方法进行了优化,详细考察了所制备的色谱柱(LZP-930G)的性能参数,并对LZP-930G色谱柱的保留行为进行了评价,探讨了GCB对LZP-930G色谱柱性能的影响。研究发现,LZP-930G色谱柱的柱效、惰性、稳定性和极性均得到了明显提高,从而改善了酸类和醇类组分的分离选择性和色谱峰峰形,实现了白酒中53种易挥发和半挥发性微量组分的同时分离,且各组分的保留时间和峰面积的相对标准偏差分别小于0.63%和4.51%(n=5)。表明GCB预涂覆技术能够用于高性能白酒分析色谱柱的制备方法。     

肟型Schiff碱Cu(Ⅱ)和Ni(Ⅱ)配合物的合成、晶体结构及光谱性质

合成了2个Schiff碱Cu（Ⅱ）/Ni（Ⅱ）配合物[Cu（L¹）₂]（1）和[Ni（L²）₂]（2）（HL¹=1-（4-（（（E）-3,5-dichloro-2-hydroxybenzylidene） amino） henyl） ethanoe O-benzyloxime,HL²=1-（4-（（（E）-4-methoxy-2-hydroxybenzylidene） amino） phenyl） ethanone O-benzyloxime）,并通过元素分析、红外光谱、紫外光谱及X射线单晶衍射分析进行了表征和分析。X射线结构表明：配合物1和2具有类似的结构,均由1个金属离子和2个配体单元组成。配合物1和2都是单斜晶系,但配合物1空间群为C2/c,而配合物2为P2₁/c。且中心金属Cu（Ⅱ）和Ni（Ⅱ）离子的空间构型均为四配位的扭曲的平面四边形结构。配合物1通过π…π和C-H…π作用形成3D超分子结构,而配合物2通过C-H…π作用形成2D超分子孔道结构。     

Preparation of chitosan/N-doped graphene natively grown on hierarchical porous carbon nanocomposite as a sensor platform for determination of tartrazine

In this work,the chitosan and N-doped graphene natively grown on hierarchical porous carbon(N-PC-G/CS) nanocomposite was obtained by ultrasonic method,as a novel sensor platform for determination of tartrazine(TT).The nanocomposite as prepared had well dispersivity in water and excellent conductivity.The N-PC-G/CS nanocomposite was characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),nitrogen adsorption-desorption,fourier transform infrared(FTIR) and electrochemical impedance spectroscopy(EIS).The application of N-PC-G/CS for determination of tartrazine(TT) was investigated by chronocoulometry(CC),cyclic voltammetry(CV) and differential pulse voltammetry(DPV).Under optimized conditions,the sensor displayed a sensitive response to TT within a wide concentration range of 0.05-15.0 μmol/L,the detection limits is 0.036 μmol/L(S/N = 3).Furthermore,this nanocomposite could be efficiently applied for determination of TT in soft drink samples.     

Maximum principles and the method of upper and lower solutions for time-periodic problems of the telegraph equations

This paper deals with the existence of bounded time-periodic solutions for the nonlinear telegraph equation

     

In situ growth and phenyl functionalization of titania nanoparticles coating for solid-phase microextraction of ultraviolet filters in environmental water samples followed by high performance liquid chromatography–UV detection

Based on TiO₂-nanoparticles coating fabricated by a one-step anodization method on titanium wire substrate, a novel phenyl functionalized solid-phase microextraction (SPME) fiber coating was prepared by simple and rapid in situ chemical assembling technique between the fiber surface titanol groups and trichlorophenylsilane reaction. The as-fabricated fiber exhibited good extraction capability for some UV filters and was employed to determine the ultraviolet (UV) filters in combination with high performance liquid chromatography–UV detection (HPLC–UV). The main parameters affecting extraction performance were investigated and optimized. Under the optimized conditions, the developed method was applied to detect several UV filters at trace concentration levels with only 8 mL of sample volume. They were determined in the range from 0.005 to 25 μg L⁻¹ with detection limits (S/N = 3) from 0.1 to 50 ng L⁻¹. The relative standard deviations (RSDs) for single fiber repeatability varied from 4.6 to 6.5% (n = 5) and fiber-to-fiber reproducibility (n = 5) ranged from 5.5 to 9.1%. The linear ranges spanned two-four magnitudes with correlation coefficients above 0.9990. Five real water samples including four Yellow River water samples and one rain water sample were determined sensitively with good recoveries ranging from 86.2 to 105.5%. The functionalized fiber coating performed good reproducible manner, high mechanical strength, good stability and long service life. Moreover, this study proposed an efficient sample pretreatment method for the determination of UV filters from environmental water samples.     

Syntheses,Structures and Spectral Properties of Mononuclear CuII and Dimeric ZnII Complexes Based on an Asymmetric Salamo‐type N2O2 Ligand

The asymmetric Salamo‐type N₂O₂ ligand H₂L and its corresponding Cu^II and Zn^II complexes [CuL] and [{ZnL}₂]·2CH₃CN were synthesized and structurally characterized. Crystallographic data of the Cu^II complex revealed that the Cu^II ion is tetracoordinate with a slightly distorted square planar arrangement forming a 2D supramolecular plane structure by hydrogen bonding and π···π stacking interactions. In the Zn^II complex, the Zn^II ions are pentacoordinate in N₂O₂ tetradentate fashion and intermolecular contacts between Zn^II and oxygen atoms result in a head‐to‐tail dimer. The Zn^II ions were found to have slightly distorted square pyramidal and trigonal bipyramidal arrangements, respectively. Hydrogen bonding interactions stabilized the Zn^II complex to facilitate self‐assembly to a 1D linear chain. The Cu^II and Zn^II complexes show intense photoluminescence with maximum emissions at approx. 426 and 411 nm upon excitation at 360 and 350 nm, respectively.     

基于碳纳米材料的毛细管电色谱固定相研究进展

碳纳米材料由于其具有独特的纳米结构、大的比表面积、较强的热稳定性、良好的导电性以及较好的吸附性能等物理化学性质,因而在分析科学、生命科学、材料科学及环境科学等领域得广泛的应用.结合国内外最新文献,对近5年来碳纳米材料在毛细管电色谱新型固定相的制备研究方面进展进行了评述,包括毛细管电色谱的分类及分离机理、毛细管电色谱柱的制备方法和优缺点,碳纳米材料(石墨烯、碳纳米管、氧化石墨烯、还原氧化石墨烯、富勒烯)的结构性质及制备方法、碳纳米材料在毛细管电色谱柱固定相中的应用及作用机理等,并对其在色谱应用领域的方向进行了展望.     

Computational prediction and biochemical characterization of novel RNA aptamers to Rift Valley fever virus nucleocapsid protein

Rift Valley fever virus (RVFV) is a potent human and livestock pathogen endemic to sub-Saharan Africa and the Arabian Peninsula that has potential to spread to other parts of the world. Although there is no proven effective and safe treatment for RVFV infections, a potential therapeutic target is the virally encoded nucleocapsid protein (N). During the course of infection, N binds to viral RNA, and perturbation of this interaction can inhibit viral replication. To gain insight into how N recognizes viral RNA specifically, we designed an algorithm that uses a distance matrix and multidimensional scaling to compare the predicted secondary structures of known N-binding RNAs, or aptamers, that were isolated and characterized in previous in vitro evolution experiment. These aptamers did not exhibit overt sequence or predicted structure similarity, so we employed bioinformatic methods to propose novel aptamers based on analysis and clustering of secondary structures. We screened and scored the predicted secondary structures of novel randomly generated RNA sequences in silico and selected several of these putative N-binding RNAs whose secondary structures were similar to those of known N-binding RNAs. We found that overall the in silico generated RNA sequences bound well to N in vitro. Furthermore, introduction of these RNAs into cells prior to infection with RVFV inhibited viral replication in cell culture. This proof of concept study demonstrates how the predictive power of bioinformatics and the empirical power of biochemistry can be jointly harnessed to discover, synthesize, and test new RNA sequences that bind tightly to RVFV N protein. The approach would be easily generalizable to other applications.     

手性钌螯合催化剂的合成及在α⁃羟基酯的动态动力学氢化反应中的应用

设计并合成了一系列基于(R)-2-(二苯基膦基)-1-苯基-N-(2′-吡啶甲基)-1-乙胺及其衍生物的手性钌螯合催化剂. 采用核磁共振波谱及高分辨质谱对其进行表征, 并给出单晶结构. 以α-羟基酯类化合物为研究对象, 通过酯的动态动力学氢化还原反应, 发展了一种合成手性二醇的方法.研究结果表明, 该催化体系能有效实现酯的氢化还原, 并获得一定的对映选择性.