固相微萃取-气相色谱-质谱联用分析水中的痕量扑草净

研究了固相微萃取－气相色谱－质谱联用测定水中扑草净的方法，采用聚丙烯酸酯（PA）萃取头，对影响固相微萃取萃取效率的萃取时间、搅拌速度、pH值以及盐度等进行了优化。在优化实验条件下，方法线性范围在0．1mg/mL-1000ng/mL之间，检出限为1．5ng/L。用该法分析了合成井水、自来水和湖水样品，回收率在85．4％－89．1％之间，相对标准偏差在1．8％－5．2％之间。本方法适合于水中痕量扑草净的分析。     

葡萄糖苷特异性固相萃取固定相的合成、表征及应用

以马来酰亚胺基修饰凝胶载体,通过β-葡萄糖胺和2-亚氨基硫代烷盐酸盐将作为配基的β-葡萄糖脒连接到载体上,合成了一种葡萄糖苷特异性固相萃取固定相,并对其固相萃取性能进行了表征.该固定相对葡萄糖苷具有特异性识别,并成功用于固相萃取分离葡萄糖苷.     

聚甲基苯基乙烯基硅氧烷固相微萃取探头的特性

用溶胶－凝胶及自由基引发交联方法，成功地制备了聚甲基苯基乙烯基聚硅氧烷和羟基硅油复合涂层的固相微萃取探头，与进口商用探头比较，研制的探头对芳香化合物具有高的萃取能力和热稳定性（350℃）以及长的使用寿命。     

苯丙共聚物-聚硅氧烷复合固相微萃取涂层的制备及性能研究

合成了苯乙烯-丙烯酸乙酯共聚物，以此聚合物与甲基聚硅氧烷色谱固定液混合作为固相微萃取头涂层。通过热分析手段考察了该涂层的热稳定性，涂层使用温度可达280℃。使用微量进样器和不锈钢毛细管，自制了SPME装置。使用该涂层萃取分析了水中氯苯系化合物，各标准样品质量浓度在0—20μg／L内与色谱峰面积呈良好线性关系（r=0．9674—0．9934），检出限为0．28—0．64ng／L，相对标准偏差为5．4％-7．7％，加标回收率为91％-99％。将自制涂层与商品涂层（PDMS、PA）进行了比较，结果表明苯丙聚合物-甲基聚硅氧烷复合涂层对氯苯系化合物具有优良的吸附特性。在固相微萃取研究和应用中，提供了新的吸附物质和色谱固定液与石英纤维结合的新途径。     

固相萃取高效液相色谱法测定冬虫夏草中的甘露醇

研究了用固相萃取预分离高效液相色谱法测定冬虫夏草中甘露醇的方法。冬虫夏草样品用水超声振荡提取后用Waters Sep-Pak—C18固相萃取小柱预分离，以HC-75钙型阳离子交换柱为固定相，水为流动相，示差折光仪为检测器检测测定冬虫夏草样品中的甘露醇含量。方法检测限为2．0μg/mL，RSD在1．1％-1．6％之间，标准回收率在96％-104％之间。     

氯丙基聚硅氧烷的合成及用作气相色谱固定相的研究

合成了几种新型的含氯丙基的取代聚硅氧烷,其热稳定性可达300～325℃,能较好地分离非极性和中等极性化合物。当固定相的苯基含量高达50％时,用8％的DCP能使其有效交联。     

聚苯乙烯-丙烯酸乙酯新型固相微萃取吸附质的研究与应用

固相微萃取(SPME)是90年代兴起的新型无溶剂样品前处理技术,基本的固相微萃取是通过石英纤维头表面涂渍的高分子层对样品中的有机分子进行萃取和预富集,然后进行色谱分析,使预处理过程大为简化,提高了分析速度及灵敏度。目前,商品SPME．GC联用装置是由美国Supclco公司生产的涂有PDMS、PA、PEG20M3种单一吸附质及4种部分交联的复合固相材料。涂层极性决定了其应用范围。     

四-(对甲基苯基)-卟啉柱前衍生固相萃取富集高效液相色谱法测定烟草中痕量铅、镉、汞

研究了用四-(对甲基苯基)-卟啉柱前衍生、固相萃取富集、高效液相色谱法测定烟草中痕量Pb、Cd、Hg的方法。烟草样品用微波消化后，用四-(对甲基苯基)-卟啉(T4MPP)柱前衍生，用Waters Sep-Park-C18固相萃取微柱萃取富集Pb、Cd、Hg的T4MPP络合物，富集倍数为50倍；然后用甲醇(内含0．01mol/L四氢吡咯-醋酸缓冲盐(pH＝10))和四氢呋喃(内含0．01mol/L四氢吡咯-醋酸缓冲盐(pH＝10))梯度洗脱为流动相，Waters Xterra TM RP18(3．9(150)色谱柱为固定相分离，用二极管矩阵检测器检测；Pb、Cd、Hg的含量在1-120ug/L范围内与峰面积呈线性关系，根据信噪比(S/N＝3)，方法检测限为：Pd0.3ug/L,Cd0.5ug/L和Hg0.3ug/L，方法相对标准偏差为2．6％-4.1％，标准回收率为91％-107％，该方法用于测定烟草中的Pb、Cd、Hg，结果令人满意。     

固相萃取光度法测定烟草中的挥发酚

研究了用Waters Sep-Park-C18固相萃取小柱萃取测定烟草样品中的挥发酚的方法。用自动水蒸汽蒸馏仪蒸馏出烟草样品中的挥发酚，4-氨基安替比林显色，显色产物可用Waters Sep-Park-C18固相萃取小柱萃取，以乙醇洗脱后用分光光度法测定，该方法可用于烟草样品中挥发酚的测定。     

固相萃取光度法测定饮用水中挥发酚的研究

研究了用Waters Sep-Park-C18小柱固相萃取光度法测定饮用水中挥发酚的方法。水样中经水汽蒸馏分离后的挥发酚，用4－氨基安替比林显色，显色产物可用C18固相萃小柱萃取、乙醇洗脱后用分光光度法测定。方法污染小，操作简便，便于批量样品处理，用于饮用水中挥发酚的测定，结果令人满意。     

Cholesterol-based dimeric liquid crystals: synthesis,mesomorphic behaviour of frustrated phases and DFT study

Chiral unsymmetrical dimeric liquid crystals consisting of a cholesterol moiety as chiral entity and a substituted salicylidene imine core (with the substituent being butyl or fluoro or chloro group) interconnected through an even methylene spacer have been synthesised and their mesomorphic properties are characterised. All the dimers exhibit enantiotropic mesophases. The butyl homologue exhibited N* phase only, the fluoro- and chloro-substituted compound exhibited frustrated blue phases (BPs), N* phase and SmC* or twisted grain boundary (TGB) phases. The occurrence of a fluid frustrated phase, the BP, in particular, observed in compounds with a polar moiety and bent optimised conformation by density functional theory (DFT) study, indicates the importance of polar structures and bent shape of the compounds. Theoretical calculation was performed in order to study the optimised conformation, polarity and electron density distribution of the synthesised cholesterol derivatives using DFT. Time-dependent density functional theory (TD-DFT) calculation also had been carried out to investigate the absorption spectra and HOMO–LUMO energies. The experimental and theoretical absorption spectra are also presented.     

Miscibility maps for polymer blends: Effects of temperature,pressure, and molecular weight

We study a Gibbs free energy model for describing the thermodynamics of compressible polymer blends in the case of nonpolar polymers. This model is a mean field model equivalent to the cell model of Prigogine et al. and close also to the model by Flory‐Orvoll and Vrij. The model is expressed as a function of the interaction energies between monomer pairs (a, b, and c), the degrees of polymerization (X_A and X_B), a close packing parameter ρ₀, the temperature, and the pressure. We derive an analytical expression regarding blend miscibility. All the already observed phase behaviors are recovered: the occurrence of two kinds of upper critical solution transition (UCST): case‐I and case‐II UCST for which the pressure has a destabilizing or stabilizing effect, respectively, and lower critical solution transition; cases where the pressure have a non‐monotonous effect on the UCST temperature; cases where the spinodal lines close up under high pressures; and the so‐called hour‐glass transition. The model allows for making explicit the effect of the different physical parameters on phase behavior. We calculate complete miscibility maps regarding the occurrence of the various possible kinds of transitions in the 2D space b/a and X_A, for different values of , applied pressure P, and chain length ratios. This approach may come as a complement to already existing, more quantitative and elaborated approaches. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 419–443     

Nd0.67M0.33MnO3(M=Mg,Ca,Sr,Ba)的制备、结构与电性

本文通过共沉淀工艺合成了系列陶瓷化合物Nd_0.67M_0.33MnO₃(M=Mg,Ca,Sr,Ba)。与传统的陶瓷法相比，其成相温度降低了400℃。经X射线衍射分析表明，所得化合物为立方钙钛矿结构，各化合物的成相温度范围受碱土二价金属离子(M²⁺)的影响。样品的四极法电阻率测试结果表明：M²⁺的离子半径对样品的导电性起决定作用，并提出了反铁磁性(AF)与铁磁性(AF)等磁性结构假设，解释了该系列化合物的导电性。     

Thermodynamic Study of the Solid-Liquid Equilibria in the Systems MIPO3-Pr(PO3)3 (MI=Na,Rb, Cs OR Ag)

A previously established equation of a stoichiometric phase liquidus curve was applied to determination of the phase diagrams of the systems M^IPO₃-Pr(PO₃)₃ (with M^I=Na, Rb, Cs or Ag). The temperature, enthalpy and entropy of fusion were calculated for each solid phase with the exception of silver polyphosphate, the crystallization field of which was very limited. The enthalpy of fusion of the polyphosphate Pr(PO₃)₃ was determined from the DTA curve. The melting enthalpy of Pr(PO₃)₃ calculated from the different binary systems was approximately equal to the measured value. The calculated temperatures and compositions were in good agreement with those determined experimentally. This revised version was published online in July 2006 with corrections to the Cover Date.     

Scattering properties,stability analysis,and phase separation of polyelectrolyte mixtures

The conditions of stability for weakly charged polyelectrolyte mixtures are analyzed from a scattering theory developed previously. In the thermodynamic limit of zero wave vector q = 0, it is found that electrostatic interaction induces a compatibility enhancement which is discussed for various cases of charge distributions. The condition of microphase separation transition at the wave vector for which the scattering is a maximum is also discussed. © 1993 John Wiley & Sons, Inc.     

Synthesis,structure and properties of new chiral liquid crystalline monomers and homopolysiloxanes containing menthyl groups

The synthesis is described of four new chiral liquid crystalline monomers (M₂–M₅ ) and their corresponding side‐chain homopolysiloxanes (P₂–P₅ ) containing menthyl groups. Chemical structures were characterised using FT‐IR or ¹H NMR spectra, and specific optical rotations were evaluated with a polarimeter. The phase behaviour and mesomorphic properties of the new compounds were investigated by differential scanning calorimetry, thermogravimetric analysis, polarising optical microscopy, UV/visible/NIR spectrocopy and X‐ray diffraction. The monomers and homopolymers with more aryl segments showed noticeably lower specific optical rotation value. The monomers M₂–M₅ formed a cholesteric or blue phase when a flexible spacer was inserted between the rigid mesogenic core and the terminal menthyl groups by reducing the steric effect. M₂–M₅ revealed enantiotropic cholesteric phase. Moreover, M₂ also exhibited a monotropic smectic A (SmA) phase, and M₄ also exhibited a cubic blue phase on cooling. The selective reflection of light shifted to the long wavelength region with increasing rigidity of the mesogenic core for M₂–M₅ . P₂–P₅ exhibited SmA phases, and the mesogenic moieties were ordered in smectic orientation with their centres of gravity in planes. Melting or glass transition temperature and the clearing temperature increased, and the mesophase temperature range widened with increasing rigidity of the mesogenic core.     

含薄荷基的手性液晶单体的合成、结构与性能研究

合成了五种新型含薄荷基的手性单体(M1～M5), 它们的结构、纯度及旋光性质通过了1H NMR, FT-IR、元素分析仪及旋光仪等手段的表征, 采用DSC, POM, UV/Vis/NIR等研究了单体的介晶性能、相行为及选择反射性能. 结果表明: 单体的比旋光度值随苯环数目的增加而降低, 通过在薄荷基与液晶核之间引入柔性间隔基元, 实现了含薄荷基单体具有液晶性能的目的. 除M1外, 其余四种单体均呈现手性近晶C (SC*)相和胆甾(Ch)相, 此外M5还出现了蓝相织构. M2～M4只在SC*相区能观察到选择反射现象, 而M5在SC*相区和Ch相区均出现明显的选择反射现象, 且随温度的升高, SC*相区的反射波长发生“红移”, 而Ch相区的反射波长则发生“蓝移”. 随着液晶核刚性的增加, 对应单体的熔点和清亮点增大, 液晶相范围变宽. 液晶核中的酯基桥键与组合方式也对单体的熔点和清亮点具有一定的影响.     

Separation,optimization, and quantification of cytokinins by a recently developed amide-embedded stationary phase

In this study, some plant growth regulators known as cytokinins [kinetin (K), zeatin (Z), thidiazuron (TDZ), benzylaminopurine (BAP), and dimethylallylaminopurine (AAP)] were separated by HPLC using an amide-embedded mixed-mode stationary phase which was synthesized by Aral et al. in recent years. The effect of mobile phase content, mobile phase pH, buffer concentration, and temperature on separation process was studied. In addition, a quantitative determination of cytokinins from Salvia limbata extract was studied, and some validation parameters such as limit of detection (LOD), limit of quantification (LOQ), and relative standard deviation (RSD) were calculated as a range of 0.03–0.1, 0.1–0.26?mg/L, and 0.03–0.08, respectively.     

Automation of static and dynamic non-dispersive liquid phase microextraction. Part 1: Approaches based on extractant drop-, plug-, film- and microflow-formation

Simplicity, effectiveness, swiftness, and environmental friendliness – these are the typical requirements for the state of the art development of green analytical techniques. Liquid phase microextraction (LPME) stands for a family of elegant sample pretreatment and analyte preconcentration techniques preserving these principles in numerous applications. By using only fractions of solvent and sample compared to classical liquid–liquid extraction, the extraction kinetics, the preconcentration factor, and the cost efficiency can be increased. Moreover, significant improvements can be made by automation, which is still a hot topic in analytical chemistry. This review surveys comprehensively and in two parts the developments of automation of non-dispersive LPME methodologies performed in static and dynamic modes. Their advantages and limitations and the reported analytical performances are discussed and put into perspective with the corresponding manual procedures. The automation strategies, techniques, and their operation advantages as well as their potentials are further described and discussed.