二甲胺修饰戊二醛交联壳聚糖树脂的制备及性能

研究了在均匀水相介质条件下，采用戊二醛稀溶液制备交联壳聚糖树脂的方法，并以三聚氯氰为活化剂，合成了二甲胺修饰戊二醛交联壳聚糖树脂．研究了该树脂的红外光谱及吸附性能．该树脂对铜(Ⅱ)和牛血清白蛋白(BSA)的吸附容量分别为42mg／g(干)和940mg／g(干)，其吸附行为均符合Freundlich等温吸附模型．该树脂制备工艺简单，机械强度较好，可作为金属离子或蛋白质分离纯化的吸附剂和色谱填料．     

Reflection absorption infrared study of the adsorption of dimethylamine on copper (1 1 0) and nickel (1 1 1) surfaces

The adsorption of dimethylamine on Cu(1 1 0) and Ni(1 1 1) has been studied by reflection absorption infrared spectroscopy. For Cu(1 1 0), adsorption was molecular at 80 and 300 K and for submonolayer dimethylamine the appearance of A′ and not A″ modes indicated C_s symmetry. Similar bonding was found for Ni(1 1 1) at 170 K. Annealing the adlayer to 350 K resulted in the formation of a new species on Ni(1 1 1), similar to that which has been identified as methylaminocarbyne on Pt(1 1 1). In contrast only molecular dimethylamine was identified on Cu(1 1 0), with H-bonded interactions at high coverage and a potential surface dimer.     

Determination of primary and secondary aliphatic amines with high performance liquid chromatography based on the derivatization using 1,3,5,7-tetramethyl-8-(N-hydroxysuccinimidyl butyric ester)-difluoroboradiaza-s-indacene

In this article, the simultaneous determination of primary and secondary aliphatic amines including dimethylamine (DMA), diethylamine and eleven primary aliphatic amines by high performance liquid chromatography (HPLC) with fluorescence detection has been achieved using a BODIPY-based fluorescent derivatization reagent, 1,3,5,7-tetramethyl-8-(N-hydroxysuccinimidyl butyric ester)-difluoroboradiaza-s-indacene (TMBB-Su). The derivatization reaction of TMBB-Su with aliphatic amines was optimized with orthogonal design experiment and the derivatization reaction proceeded at 15 °C for 25 min. The baseline separation of these derivatives was carried out on a C₈ column with methanol-tetrahydrofuran-50 mM pH 6.50 HAc-NaAc buffer (55/5/40, v/v/v) as a mobile phase. Detected at the excitation and emission of 490 and 510 nm, respectively, the detection limits were obtained in the range of 0.01-0.04 nM (signal-to-noise ratio = 3). The proposed method has been applied to the determination of trace aliphatic amines in viscera samples from mice without complex pretreatment or enrichment method. The recoveries ranged from 95.1% to 106.8%, depending on the samples investigated.     

乙胺和二甲胺分子(n_N,3s)里德堡态共振的多光子电离

MPI质谱研究作为化学分析和研究光物理过程的工具受到广泛的重视[1－4]．REMPI的特征过程是，首先分子吸收。个光子共振激发到中间态，然后处于中间激发态的分子再吸收n个光子激发到电离连续区[5]．REMPI的谱特征可以给出中间态分布的详细信息[6]，利用REMPI过程可研究单光子跃     

胺基化合物修饰戊二醛交联壳聚糖树脂的合成及其红外光谱研究

研究了以三聚氯氰为活化剂,正丁胺、二甲胺、三甲胺、三乙胺、苯甲胺、对甲基苯胺、对氨基苯磺酸修饰戊二醛交联壳聚糖的制备及其红外光谱。壳聚糖1 155 cm-1的糖苷键ν_(C—O—C)吸收峰、899 cm-1的环振动吸收峰和1 030 cm-1的伯羟基ν_(C—OH)吸收峰基本不变。在3 430～3 440 cm-1的ν_(O—H)和ν_(N—H)吸收峰稍有变化,1 400～1 384 cm-1的δ_(C—H)吸收峰变化较明显。氨基化修饰交联壳聚糖仲羟基的ν_(C—OH)吸收峰由1 095 cm-1移至1 060～1 070 cm-1。三聚氯氰活化交联壳聚糖在803～812 cm-1和1 584～1 590 cm-1出现均三嗪环骨架振动吸收峰。随取代度和脱乙酰度不同,壳聚糖的酰胺Ⅰ,Ⅱ,Ⅲ峰强度变化明显。伯仲胺修饰交联壳聚糖在1 517～1 530 cm-1出现质子化氨基δ_(N—H)吸收峰,三甲胺、三乙胺修饰交联壳聚糖此峰消失或减弱,但在1 400～1 500 cm-1出现一组ν_(C—N)吸收峰。     

Highly improved electrocatalytic oxidation of dimethylamine borane on silver nanoparticles modified polymer composite electrode

Dimethylamine borane (DMAB) is a promising fuel alternative for fuel cell applications. In this work cyclic voltammetric behavior of DMAB was investigated on the polymerized aminophenol film decorated with Ag nanoparticles in alkaline media. The polymer film was formed on the glassy carbon electrode by electrochemical technique and then, the surface was modified with Ag nanoparticles. The surface of the modified electrode was identified by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy techniques. The developed electrode has displayed high electrocatalytic activity for DMAB oxidation in alkaline media depending on the supporting electrolyte concentration. Experimental parameters such as cycle number used in electropolymerization of p-aminophenol, deposition of Ag nanoparticles and supporting electrolyte were optimized.     

A new solvent system for the separation of Th4+, UO 2 2+ and Zr4+ in the presence of common anions by thin-layer chromatography

Summary A TLC method has been developed for separating Th⁴⁺, UO₂ ²⁺ and Zr⁴⁺ in the presence of some common anions using a dimethylamine/acetone/formic acid mobile phase. Capacity factors, separation factors and resolution for the separation of Th⁴⁺ from UO₂ ²⁺ have been evaluated. The effect of the pH of the sample on R_F values of Th⁴⁺, UO₂ ²⁺, Ni²⁺ and Cu²⁺ has also been examined.     

A new selective method for dimethylamine in water analysis by liquid chromatography using solid-phase microextraction and two-stage derivatization with o-phthalaldialdehyde and 9-fluorenylmethyl chloroformate

A new method is presented for the determination of DMA in water as its 9-fluorenylmethyl chloroformate (FMOC) derivative using solid-phase microextraction (SPME) and liquid chromatography. The method is based on the employment of SPME fibres coated with carbowax-templated resin (CW-TR) for analyte extraction and derivatization. The fibres were successively immersed in the samples, in a solution of o-phthalaldialdehyde and N-acethyl-l-cysteine (OPA–NAC) and finally, in a solution of FMOC. OPA–NAC reacted on the fibre with possible primary aliphatic amines present in the samples, particularly with PA which is a direct interferent in the determination of DMA with FMOC. In such a way, the formation of PA–FMOC during the second stage was prevented, and thus the method was selective for DMA. The proposed procedure was applied to the determination of DMA in the 1.0–10.0 μg/mL range. The method provided suitable linearity, accuracy and reproducibility, and limits of detection and quantification of 0.3 and 1.0 μg/mL, respectively. The applicability of the method for the determination of DMA in different types of water is shown.     

Determination of different classes of amines with capillary zone electrophoresis and contactless conductivity detection

The use of contactless conductivity detection for the determination of different organic amines in CE was successfully demonstrated. Aliphatic non UV-absorbing species could be determined along absorbing compounds by measuring the conductivity of their protonated forms. The species tested included short-chained aliphatic primary, secondary and tertiary amines, branched aliphatic amines, diamines, hydroxyl-substituted amines as well as species incorporating aromatic and non-aromatic cyclic moieties. Highest sensitivity was obtained with BGE solutions containing solely acetic acid. A concentration of 0.5 M at a pH value of 2.5 was used. Detection limits were in the order of 1 microM. Complete separation of cis- and trans-1,2-diaminocyclohexane could be achieved by adding 18-crown-6 as modifier to the electrolyte solution.