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31.
32.
综述了近8年来液相平行合成和组合合成中应用的不同技术, 包括可溶性载体、氟合成技术、离子液体、固相试剂树脂以及低聚乙烯二醇(OEG)衍生物的应用等几方面内容. 论述了它们的基本原理以及相关的应用实例, 并着重强调了目标化合物的分离纯化方法. 相似文献
33.
An application of automated on-line HPLC-HRGC is described for direct analysis of edible oils for migrated polymer additives. The sample preparation, separating the additive from the oil triglycerides, is carried out using normal phase HPLC. The fraction of the eluent containing the additive is automatically transferred to a HRGC where a second and final separation of the additive from minor oil components takes place. The method compares well with off-line separation methods. Migration data for Tinuvin 1577 from PET and PC polymers as well as an unspecified experimental polymer is given. The advantages and disadvantages of using different edible oils as food simulants are discussed. 相似文献
34.
烟碱分子烙印聚合物的吸附特性 总被引:10,自引:0,他引:10
利用分子烙印技术,以烟碱为烙印分子,甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EDMA)为交联剂,合成了对烟碱具有特异性作用的分子烙印聚合物P(Nic);通过平衡吸附实验,评价了其对烟碱的亲和力和选择性。与非烙印聚合物相比,P(Nic)对烟碱表现了很高的亲和力;Scatchard分析表明在P(Nic)中存在对烟碱有不同的亲和力的两类作用位点。通过与氨基吡啶类物质在P(Nic)上的吸附行为比较,表明P(Nic)对烟碱具有很好的选择性。本工作证明了用P(Nic)作为固相萃取(SPE)材料选择性地从烟草烟雾中提取烟碱的可能性。 相似文献
35.
Decomposition of Toluene and Acetone in Packed Dielectric Barrier Discharge Reactors 总被引:2,自引:0,他引:2
Chung-Liang?ChangEmail author Tser-Sheng?Lin 《Plasma Chemistry and Plasma Processing》2005,25(3):227-243
The influences of TiO2 catalytic material and glass pellet packing on the decomposition efficiency of toluene and acetone in air by dielectric barrier discharge (DBD) reactors were experimentally investigated in this study. The effects of both packing materials on the formation of byproducts such as CO and CO2 were also evaluated. Experimental results indicate that the introduction of glass materials into the plasma zone of a wire-tube reactor would improve the decomposition efficiency of toluene and acetone compared to a nonpacked reactor. The apparent decomposition rate constant of a glass packed-bed reactor was 4.5–4.8 times greater than that of a nonpacked reactor. The results also indicate that the decomposition rate constant of toluene was approximately 2.6 times higher than that of acetone no matter which type reactor was utilized. The application of TiO2 coated pellets in DBD reactors will enforce the hydrocarbon byproducts to further be oxidized to CO2, notwithstanding, it will not significantly improve the performance of the reactors in the decomposition of toluene and acetone, and in the formation of CO. The results show that the best selectivity of CO2 for acetone decomposition in a TiO2 coated pellets packed-bed reactor was approximately 40% higher than that in a glass packed-bed reactor. 相似文献
36.
Preparation, characterization and properties studies of quinine-imprinted polymer in the aqueous phase 总被引:4,自引:0,他引:4
The uniform-sized spherical molecularly imprinted polymers were successfully prepared through molecular imprinting technology
by two-step seed swelling and mini-emulsion polymerization in the aqueous condition using quinine as template molecules and
methacrylic acid (MAA) as functional monomer. The polymers were characterized by IR spectra, thermal-weight analysis, scanning
electron microscope and laser particle size analysis. The properties of imprinted polymers were investigated in different
organic phases and aqueous media. In the organic media, results suggested that polar interactions (hydrogen bonding, ionic
interactions) between acidic monomer/polymer and template molecules are mainly responsible for the binding and recognition;
whereas in the aqueous medium, a considerable recognition effect was also obtained where the ionic (electrostatic) interaction
and hydrophobic interaction play an important role. The experiments of binding different substrates indicated that the MIPs
possessed an excellent rebinding ability and inherent selectivity to quinine.
__________
Translated from Zhongshan Dcocue Xuebao/Acta Scientianum Natralium University Sunyatseni, 2005, 44(3)(in Chinese) 相似文献
37.
本文报道了在不可逆电极过程的强催化体系中,当采用快速方波扫描时,正、逆向电流将出现峰形。依据实验结果,提出了“迁出-进入”的等浓度面理论模型,推导了并讨论了电流方程式。结果表明,文中提出的理论能较好地说明实验结果。 相似文献
38.
Development of new lubricating grease formulations using recycled LDPE as rheology modifier additive
The recovery of plastic waste but also its applicability in product development may be an incentive to industry, since the use of such plastics represents a cheaper source of raw material. The aim of the present paper is to study the feasibility of recycling polyolefins as additives to improve the rheological properties of lithium 12-hydroxystearate lubricating greases. The effects that both soap and recycled low-density polyethylene (LDPE) concentration exert on the rheology of lithium lubricating greases and its relationship with grease microstructure are discussed in this work. In this way, different lubricating grease formulations were manufactured by modifying the concentration of lithium 12-hydroxystearate and content of recycled LDPE, according to a RSM statistical design. These lubricating greases were rheologically characterized through small-amplitude oscillatory shear (SAOS) and viscous flow measurements. In addition to these, scanning electronic microscopy (SEM) observations and mechanical stability tests were also carried out. Recycled LDPE was found to be an effective additive to modify grease rheology, acting as filler in the soap entangled microstructure. The values of both apparent viscosity and viscoelastic functions in the linear viscoelastic region increase with soap and recycled polymer concentrations. However, the addition of recycled LDPE distort the microstructural network of these greases resulting greases with less relative elastic characteristics and poorer mechanical properties as LDPE content increases. 相似文献
39.
《Electroanalysis》2003,15(4):254-262
The new electrochemical double pulse technique, known as additive differential normal pulse voltammetry (ADNPV) when there is no restriction on the duration of both pulses, and additive differential pulse voltammetry (ADPV) when t2?t1, has been applied to a pseudo‐first‐order catalytic mechanism. The expressions obtained here are applicable to planar and spherical electrodes, of any radius. This is of great interest since the size of the electrode plays an important role in the preponderating of diffusive and kinetics processes. The signal obtained with this technique presents the same morphological characteristics as the triple pulse technique, double differential pulse voltammetry (DDPV) and is more advantageous than DDPV and than the double pulse one, differential pulse voltammetry (DPV). 相似文献
40.
We evaluated a novel strategy for high-sensitivity DNA fragment analysis in a conventional glass double-T microfluidic chip. The microchip allows for a DNA on-channel concentration based on base stacking (BS) with a microchip capillary gel electrophoretic (MCGE) separation step in a poly(vinylpyrrolidone) (PVP) sieving matrix. Depending if low conductivity caused a neutralization reaction between the hydroxide ions and the run buffer component Tris+, the stacking of DNA fragments were processed in the microchip. Compared to a conventional MCGE separation with a normal electrokinetic injection, the peak heights of 50-2650-base pair (bp) DNA fragments on the MCGE-BS separation were increased 3.9-8.0-fold. When we applied the MCGE-BS method to the analysis of a clinical sample of bovine theileria after PCR reaction, the peak height intensity of the amplified 816-bp DNA fragment from the 18S rRNA of T. buffeli was enhanced 7.0-fold compared to that of the normal injection method. 相似文献