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31.
H. G. Struppe F. Franke J. Hofmann B. Ondruschka 《Journal of chromatography. A》1996,750(1-2):239-244
In contrast to usability of Curie-point pyrolysis at 700°C directly attached to gas chromatography-mass spectrometry (GC-MS) for determination of organic wood preservatives in waste wood samples the investigation method reported here consists of thermal desorption at temperatures about 260°C in connection with GC-MS for peak identification or GC with flame ionization detection for quantitative analyses. So-called “modified closeable sampling columns” are used as batch-reactor in thermal desorption experiments. Desorbed vapours can be introduced on capillary columns without sample discrimination and without a disturbing lost of resolution. In this manner a lot of individual polycyclic aromatic hydrocarbons were determinated in waste wood samples, especially in railway sleepers. 相似文献
32.
用水热晶化法合成了MZr_2(ASO_4)_3(M=Na,K,Rb,Cs)系列化合物。研究了反应物浓度、配比及不同砷源等水热晶化条件对产物物相的影响。用XRD、IR和Raman光谱对产物进行了表征。4种晶体的振动光谱由钠到铯呈现出规律性变化。 相似文献
33.
A competitive enzyme-linked immunosorbent assay (ELISA) was developed for the quantitative detection of the insect growth regulator fenoxycarb. Polyclonal rabbit antisera, raised against protein conjugates of four haptenic derivatives of fenoxycarb, were utilized in immobilized antigen-based, competitive immunoassays. With ELISA systems that were both hapten- and carrier-heterologous, most antiserum titers fell in the range of 1:1000-1:30,000. Assay conditions, including concentrations of antisera and coating antigens, were optimized. The effect of pH, organic solvents, and various blocking agents was also investigated. A hapten-homologous and two hapten-heterologous indirect ELISAs allowed fenoxycarb determination in the range of 0.1-85 ng ml−1 with apparent IC50 values of 1.2-2.8 ng ml−1. Cross-reactivities with a number of compounds (e.g. pesticides of related structure, hapten synthesis intermediates, fenoxycarb metabolite, photodegradation products) were determined, and the assay proved highly selective for fenoxycarb. In particular, no significant interference was found with selected pyrethroid and juvenile hormone analog insecticides, phenoxyacetic acid herbicides, and photodegradation products of fenoxycarb. Using spiked water samples, assay performance was validated by SPME/GC-MS. 相似文献
34.
使用穆斯堡尔谱,ESR和XRD等技术表征了未添加助剂和添加LiCl的Fe2O3/SiO2催化剂.XRD结果指出,添加LiCl的Fe2O/SiO2催化剂出现铁酸盐和α-方石英的衍射峰,这种结果的出现与该催化剂有较高的C2烃选择性密切相关。穆斯堡尔谱结果表明:添加LiCl的Fe2O3/SiO2催化剂有更高的结构对称性.这种结构对分子氧的活化起着重要的作用.氯的存在大大降低了氧的离解吸附的速率,减少了原子氧的吸附位的数目,并可除去吸附的原子氧,该氧种对COx的生成有利. 相似文献
35.
A procedure has been developed to coat micron-sized poly(styrene-co-3-trimethoxysilyl propyl methacrylate) microspheres with
a smooth layer of polysiloxane by the hydrolysis and condensation of methyl trimethoxylsilane (MTMS). Firstly, polystyrene
microspheres containing silanol groups were prepared by conventional dispersion polymerization using 3-(trimethoxysilyl) propyl
methacrylate (MPS) as a functional comonomer in an ethanol/water medium. Secondly, the synthesis of the polysiloxane shell
was carried out using a sol–gel process of MTMS. The thickness of the shells can be easily varied with different copolymer
seeds and MTMS feed ratio. When we used copolymer particles with 2.00 μm diameter as seeds, the thickness of the polysiloxane
shells can be varied from 0.10 to 0.18 μm. The core/shell structure of the composite microspheres was characterized by transmission
electron microscope (TEM). 相似文献
36.
Shou‐Ri Sheng Xiao‐Ling Liu Yong‐Fen Tong Lie Chen Hong‐Li Wen Cai‐Sheng Song 《中国化学会会志》2005,52(5):943-946
Several new methyl substituted poly(aryl ether ketone)s containing sulfone linkage with inherent viscosities of 0.62–0.84 dL/g have been prepared from 4,4′‐bis(2‐methylphenoxy)diphenylsulfone and 4,4′‐bis(3‐methylphenoxy)diphenylsulfone with terephthaloyl chloride and isophthaloyl chloride by electrophilic Friedel‐Crafts acylation in the presence of DMF with anhydrous AlCl3 as a catalyst in 1,2‐dichloroethane, respectively. These polymers having weight‐average molecular weight in the range of 71,000–49,000 are all amorphous and show high glass transition temperatures ranging from 167 °C to 191 °C, excellent thermal stability at temperatures over 400 °C in air or nitrogen, high char yields of 51–58% in nitrogen and good solubility in CHCl3 and polar solvents such as DMF, DMSO and NMP at room temperature. 相似文献
37.
IR and ~(29)Si NMR were used to determine the structures of ladderlike polymer polyphenylsilsesquioxanes (PPS). It was found that PPS with lots of defects had a wide and strong absorption band in 1000—1400 cm~(-1) with only one sharp peak at 1137 cm~(-1) while two peaks (1130 and 1045 cm~(-1) were observed for PPS with perfect ladderlike structure. Branching and crosslinking of PPS lead to the reduction of 1045 cm~(-1) peak. ~(29)Si NMR spectra, however, showed two peaks (δ=-78 ppm and -87 ppm when δ_(HMDS)=0 ppm) for defective or branched PPS. The -87 ppm peak is related to the ladderlikely constructed Si atoms and -78 ppm corresponds to defective Si atoms. PPS with defects less than 0.1% chain units was obtained by azeotropic polycondensations. 相似文献
38.
39.
聚(甲基丙烯酸甲酯—二甲基二烯丙基氯化铵)的合成及表征 总被引:1,自引:0,他引:1
以水和乙醇作混合溶剂,用逐步滴加甲基丙烯酸甲酯的方法,通过自由基聚合,由溶解性和共聚活性差异较大的两种单体MMA和二甲基二烯丙基氯化铵合成了新型含阳离子共聚物聚,并用IR和^1H-NMR进行了分析表征。该共聚物溶于丙酮和水组成的二元溶剂,并与P(MMA-MAA)有较强的分子复合能力。 相似文献
40.
GU Jin-ying HU Xiao-jun SHI Xian-fa LI Yan-jun QI Yong-lu JI Liang-nian 《高等学校化学研究》2007,23(2):241-244
Introduction Calixarenes are versatile host molecules for molecular recognition and supram olecular assembly be-cause its functional groups can be readily introduced in-to the phenolic OH or the para position to realize a wide variety of functions[1-5]. 相似文献