On-site preconcentration and trace metal ions determination in the Okavango Delta water system, Botswana

Microcolumns containing 8-hydroxyquinoline azo-immobilized on controlled pore glass were incorporated in a field sampler for on-site collection, isolation and preconcentration of trace metal ions in waters of the Okavango Delta, Botswana. Sequestered trace metal ions were recovered by elution with 0.5 ml of 1.5 M nitric acid, and determined by graphite furnace atomic absorption spectrometry (GFAAS). This sampling and enrichment method minimizes sample contamination, and collection of large volumes of water samples for transporting, over long distances, to analytical laboratories is avoided.Data reported comprise one of the initial surveys on trace metal ion concentrations in waters of the Okavango Delta, Botswana. In waters with more efficient mixing, dissolved metal ion concentrations found were generally low with slightly elevated levels of manganese (7-19 μg l⁻¹), zinc (2.7-4.8 μg l⁻¹), nickel (0.2-2.5 μg l⁻¹) and copper (0.3-2.1 μg l⁻¹). For each trace metal ion, concentration levels seem to reflect zones of varying water conveyance, and show no obvious temporal and spatial variations apart from a slight increment from the inlet in the upper Delta to the outlets in the lower Delta.     

核酸-8-羟基喹啉-钪(Ⅲ)体系的荧光特性及其分析应用

在ＰＨ ６．８～８．８的酸度范围内，小牛胸腺脱氧核糖核酸（ｃｔＤＮＡ），鱼精子脱氧核糖 核酸（ｆｓＤＮＡ）以及酵母核糖核酸（ｙＲＮＡ）分别与８－羟基喹啉（８－ＨＱＬ）和Ｓｃ（Ⅲ）形成的三元 体系受 ２６４～２７０ ｎｍ紫外光激发将发出 ４９０～４９６ ｎｍ的荧光。与 Ｓｃ（Ⅲ）和 ８－ＨＱＬ 二元络合 物相比，三元体系的荧光量子产率增大，荧光寿命增长，最大发射波长紫移约 １０ ｎｍ。６个合 成样品的分析结果表明，利用 Ｓｃ（Ⅲ）／８－ＨＱＬ能十分灵敏的测定脱氧核糖核酸。     

Characterization of SiO2-P2O5-ZrO2 Sol-Gel/NAFION™ Composite Membranes

Composite membranes were prepared by (a) infiltrating NAFION with SiO₂-P₂O₅-ZrO₂ sol, and (b) recasting a film using NAFION solution containing SiO₂-P₂O₅-ZrO₂ sol. The membranes were characterized by Differential Thermal Analysis and ac-impedance spectroscopy as a function of relative humidity. The influences of the heat treatment (80°C–150°C) and cleaning on the electrical properties were investigated. The incorporation of SiO₂-P₂O₅-ZrO₂ gels into NAFION lead to improvements in its thermal stability and proton conductivity.     

锆(Ⅳ)同7-碘-8-羟基喹啉-5-磺酸三元混配化合物的形成及其荧光光度研究

在 EDTA 存在下,Zr(Ⅵ)与 H_2QSI 在 pH6.0时形成三元荧光配合物。其组成为Zr:H_2QSI:EDTA=1:1:1。荧光强度与锆离子在0.1～1.0μg/10ml 范围内呈现线性关系。对EDTA 的作用机理作初步探讨。     

稀土丙烯酸盐与8－羟基喹啉三元固态配合物的合成与表征

稀土丙烯酸盐与８－羟基喹啉三元固态配合物的合成与表征李长正，王学智，唐宁，谭民裕（兰州大学化学系兰州７３００００）关键词：稀土，丙烯酸，８－羟基喹琳，三元配合物８－羟基喹琳因其具有优良的配位性能而被广泛应用于金属离子的分离和分析中［１］。文献中有关它...     

Host-guest complexes of cucubit[8]uril with phenanthrolines and some methyl derivatives

Cucurbituril a molecular container (or host) has a rigid hollow interior cavity which is large enough to accommodate, one or more, smaller molecules (or guests). The cavity is accessible through two carbonyl portal openings. Molecules or guests enter the …     

微波辐射下一步合成3-氨基-4-氰基-1-芳基-5,6,7,8-四氢异苯并吡喃

亚环己基马来腈与芳醛在哌啶催化下,经微波辐射一步合成3-氨基-4-氰基-1-芳基-5,6,7,8-四氢异苯并吡喃,反应7～11min,产率57%～94%.     

π-Bindungsbeitrag in Boranen, 2. Mitt.:Ab initio- und Kraftfeld-Rechnungen von Vinyldifluorboran

Ab initio calculations on vinyldifluoroborane yield a -contribution of 23 kJ/mol (5.5 kcal/mol) mainly due to the C=C bond and not to the lone pairs of the fluorine atoms. The rotational barrier was also determined. The force field calculations favour the interpretation of the bond structure derived from the theab initio results.

     

5,7′-(亚甲胺基)-二-8-羟基喹啉的合成及其理论研究

以4-甲基苯磺酸作催化剂、用三乙胺调节pH值约为9的条件下, 由5-甲酰基-8-羟基喹啉和5-氨基-8-羟基喹啉合成了新的5,7′-(亚甲胺基)-二-8-羟基喹啉, 利用IR, UV, ¹H NMR, MS确认了分子结构, 比较研究了其光致发光特性, 运用Gaussian 98量子化学程序包, 采用B3LYP密度泛函(DFT)的方法, 在6-31G(d,p)水平上对分子的几何构型进行结构优化; 并对目标化合物的稳定结构通过计算预测其振动光谱, 计算结果与实验值基本相符.     

Phosphorescence lifetime of naphthalene and phenanthrene in aggregated aromatic molecule-β-cyclodextrin-precipitant complexes

Aggregated aromatic molecule--cyclodextrin-precipitant complexes exhibit long-lived phosphorescence at room temperature in water after the chemical binding of oxygen. The temperature dependences of the phosphorescence lifetimes of naphthalene-h₈, naphthalene-de, and phenanthrene in the aggregates were measured. For example, the phosphorescence lifetimes of naphthalene-d₈ aggregated with -cyclodextrin and cyclohexane are equal to 25.1, 17.6, and 6.8 s at 77, 276, and 347 K, respectively, and that of phenanthrene aggregated with isooctane and -cyclodextrin are 3.24, 3.06, and 1.26 s at 268, 274, and 335 K, respectively. The temperature dependences of the phosphorescence lifetimes at room temperature are determined by the rate constants of the radiative and nonradiative transitions from the triplet state of an aromatic molecule.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2225–2228, September, 1996.