荧光法测定香烟烟气中总的多环芳烃含量

有机溶剂萃取不同香烟烟气焦油中有机物 ,用荧光法分析了烟草的总体特征光谱 ,同时以多环芳烃菲作参比 ,定量分析了各种品牌香烟在去掉过滤嘴和保留过滤嘴条件下 ,烟气在溶剂中的多环芳烃含量 ,为卷烟品质、烟气中有害物质的评价提供了一种实用的测定方法     

Aromatic spectral editing techniques for magic-angle-spinning solid-state NMR spectroscopy of uniformly 13C-labeled proteins

The four aromatic amino acids in proteins, namely histidine, phenylalanine, tyrosine, and tryptophan, have strongly overlapping ¹³C chemical shift ranges between 100 and 160 ppm, and have so far been largely neglected in solid-state NMR determination of protein structures. Yet aromatic residues play important roles in biology through π–π and cation–π interactions. To better resolve and assign aromatic residues' ¹³C signals in magic-angle-spinning (MAS) solid-state NMR spectra, we introduce two spectral editing techniques. The first method uses gated ¹H decoupling in a proton-driven spin-diffusion (PDSD) experiment to remove all protonated ¹³C signals and retain only non-protonated carbon signals in the aromatic region of the ¹³C spectra. The second technique uses chemical shift filters and ¹H–¹³C dipolar dephasing to selectively detect the Cα, Cβ and CO cross peaks of aromatic residues while suppressing the signals of all aliphatic residues. We demonstrate these two techniques on amino acids, a model peptide, and the microcrystalline protein GB1, and show that they significantly simplify the 2D NMR spectra and both reveal and permit the ready assignment of the aromatic residues' signals.     

不同溶剂中取代基对芳香胺红外吸收光谱的影响

对２１种芳香胺在不同极性的溶剂中测定了红外光谱,并对不同取代基对氨基的对称伸缩动和非对称伸缩振动吸收峰峰位的影响进行了讨论。甲基在不同极性的溶剂中表现不同的电子效应;甲氧基处于氨基的邻位的电子效应和处于间位时不同,氯和硝基取代基使氨基的两吸收峰均向蓝移,氨基取代基使氨基的两吸收峰向红移。     

Effects of benzene and naphthalene addition on soot inception in a well-stirred reactor/plug flow reactor

A well-stirred reactor (WSR) followed by a plug flow reactor (PFR) is being used to study soot inception. Soot size distributions were measured using two different dilution probes followed by a nano-differential mobility analyzer (nano-DMA). One of the dilution probes was developed for the PFR section, while the second probe was specifically developed for use in the WSR section. Results are presented on the effect of residence time on the soot size distributions obtained for fixed dilution ratio and equivalence ratio. In addition, a technique to inject aromatics and PAH species in the transition region between the WSR and PFR was developed. Results are presented on the effect of benzene and naphthalene on the soot size distributions obtained for differing seeding concentrations and residence times. The results demonstrate for the first time the sensitivity of the soot particle size distribution to the seeding of aromatic species in a WSR/PFR.     

Magnetic field effect on indole exciplexes: an anomalous dielectric dependence

Individual exciplex formation between various aromatic hydrocarbons, anthracene, pyrene, all-s-trans-1,4-diphenylbuta-1,3-diene and a heteroaromatic amine, 1,2-dimethylindole, was investigated by steady-state fluorescence and magnetic field effect (MFE). A comparative study was carried out with two other exciplex systems 9-cyanophenanthrene-1,2-dimethylindole and 9-cyanophenanthrene-N-methylindole. The extent of charge transfer and dielectric dependence of MFE reveals the potential role of specific interactions related to exciplex geometry.     

分子印迹材料选择性截留卷烟烟气中芳胺的研究

采用分子印迹技术合成了一种对1-萘胺有高度选择性的分子印迹聚合物材料。应用固相萃取吸附试验研究了该聚合物对1-萘胺及其结构类似物的选择特性,表明印迹聚合物材料对4种芳胺类物质表现出良好的选择性结合能力。将所制备的印迹聚合物按不同剂量添加到卷烟嘴棒中,考察其对卷烟烟气中芳胺的截留效果。结果显示,该分子印迹材料能选择性截留卷烟烟气中的1-萘胺、2-萘胺、3-氨基联苯和4-氨基联苯等烟气有害成分;当印迹聚合物添加量为50mg时,卷烟烟气中芳胺的降低率达到30%。     

Densities, speeds of sound and viscosities of binary liquid mixtures of octan-2-ol with benzene and halobenzenes at 298.15 and 303.15 K

Densities ρ, speeds of sound u, viscosities η and refractive indices n_D of binary mixtures of octan-2-ol with benzene, chlorobenzene and bromobenzene have been measured over the entire range of composition at 298.15 and 303.15 K and atmospheric pressure. From the experimental data, excess molar volumes V^E, isentropic compressibilities κ_S, excess isentropic compressibilities κ_S^E, and deviations of speeds of sound u^D, have been calculated at 298.15 and 303.15 K. These excess functions have been fitted to the Redlich-Kister polynomial equation. The viscosity data have been correlated using Kendall-Monroe, Grunberg-Nissan, Tamura-Kurata, Hind-Mclaughlin Ubbelohde and Katti-Chaudhary viscosity models, and McAllister's three-body interaction model at different temperatures.     

多氯甲基芳烃的合成与表征

以甲苯、乙苯、异丙苯、间二甲苯和均三甲苯为原料,在由路易斯酸、有机酸和无机酸所组成的新型复合催化剂协同催化下,经多氯甲基化反应制备了2,4,6-三(氯甲基)甲苯、2,4,6-三(氯甲基)乙苯、2,4,6-三(氯甲基)异丙苯、2,4,6-三(氯甲基)间二甲苯和2,4,6-三(氯甲基)均三甲苯.利用IR、1H NMR、13C NMR等手段对所合成产物的结构进行了表征,在优化反应条件下,5种产物的收率分别可达 24.5％、31.7％、15.3％、78.1％和89.6％.     

恒能量同步荧光光谱法测定食用油中多环芳烃

用12%（w/V）的氢氧化钾-乙醇溶液皂化食用油的脂肪酸,以环己烷萃取皂化液中的多环芳烃,经浓缩,柱层析纯化并浓缩,取微量试样液稀释后,通过选择合适能量差,建立了同步荧光法测定食用油中多环芳烃含量的新方法,其线性范围为5—1000ng.mL-1,检出限在0.04—15.21ng.mL-1之间,平均加标回收率在81.94%—90.06%之间。该方法具有快速、简便、准确等特点。