非线性偏最小二乘导数分光光度法同时测定复方新诺明中二组分的含量

构造了导数光谱与多组分浓度间的非线性模型 ,以偏最小二乘法估计模型参数 ,建立了同时测定两组分的非线性偏最小二乘导数分光光度法 ,方法用于复方新诺明中磺胺甲唑SMZ(Sulfamethoxazole)和甲氧苄啶TMP(Trimethoprim)含量的测定 ,10份模拟样中SMZ ,TMP的回收率分别为 99 8%和 10 0 1% ,RSD分别为 1 3%和 1 6 %。结果明显好于线性偏最小二乘导数分光光度法。用该法测定复方新诺明片中的二组分含量测定结果与药典方法一致 ,该法为复方制剂的分光光度分析提供了更为理想的新途径。     

火焰原子吸收法测定小麦品种籽粒中铁锰锌含量

用火焰原子吸收分光光度法,测定6种不同类型的冬小麦品种籽粒中铁、锰、锌微量元素的含量。结果表明铁、锰、锌的回收率分别为10309%,10290%和10119%,相对标准偏差(RSD)分别在394%,167%和269%以内,并以GBW08503小麦粉标准样品进行比较测定,结果满意。该方法简便、快速、准确。测定结果为研究小麦品种籽粒中微量元素的含量与小麦品质的关系提供依据。     

La1-x-yBaxREyMnO3复合氧化物的制备及其对甲烷燃烧的催化性能

 以Na2CO3·10H2O和NaOH混合碱为沉淀剂,采用共沉淀法制备了钙钛矿型结构的La1-x-yBaxREyMnO3(RE=Dy或Y)复合氧化物超细粒子. 该复合氧化物超细粒子具有较大的比表面积和良好的热稳定性(经700和1000 ℃焙烧后,其比表面积仍分别可达到47.0和16.9 m2/g). 随着LaMnO3中的La3+被Ba2+及稀土离子Dy3+或Y3+部分取代后,样品显示出良好的热稳定性及对甲烷燃烧的高催化活性.     

A dinuclear CoII complex: bis(μ‐di­hydrogen phosphato‐κ2O:O′)­bis­[(bipyridine‐κ2N,N′)(di­hydrogen phosphato‐κO)­cobalt(II)]

The title compound, [Co₂(H₂PO₄)₄(C₁₀H₈N₂)₂], is dinuclear, centred on a symmetry centre of the P space group. Each Co atom has a distorted square‐pyramidal coordination involving two N atoms from a bi­pyridine mol­ecule and three O atoms from two bridging and one terminal di­hydrogen ortho­phosphate anion. The molecular structure and packing are stabilized by intermolecular hydrogen‐bond interactions.     

Silver(I) Complexes with a Bulky Anthracene‐Based Dicarboxylic Ligand: Syntheses,Crystal Structures,and Luminescent Properties

To explore the influence of anthracene skeleton with a larger conjugated π‐system on the structures and properties of its complexes, two Ag^I–carboxylate complexes based on anthracene‐9,10‐dicarboxylate (L) were synthesized and characterized: [{[Ag(L)][Ag(dmpy)₂]}_∞] ( 1 ) and [{[Ag₂(L)(bipy)₂]}_∞] ( 2 ) (dmpy = 2,6‐dimethylpyridine and bipy = 4,4′‐bipyridine). Complex 1 has an interesting framework consisting of anionic chains {[Ag(L)]^–}_∞ and the mononuclear cationic units [Ag(dmpy)₂]⁺, which is further assembled to form networks along the different crystallographic directions by the intermolecular C–H ··· Ag hydrogen‐bonding interactions. Complex 2 takes a ladder‐like chain structure by incorporating 4,4′‐bipyridine (bipy) as a bridging co‐ligand, which is further interlinked to generate a planar network through interchain Ag–Ag bonding contacts. The steric bulk of anthracene ring in L may play an important role in the formation of 1 and 2 . Moreover, the luminescent properties of the 1 and 2 were investigated in detail.     

A new route for simple and rapid determination of hydrogen peroxide in RAW264.7 macrophages by microchip electrophoresis

A new method using MCE with LIF detection was developed for the determination of hydrogen peroxide (H₂O₂). Bis(p‐methylbenzenesulfonyl)dichlorofluorescein, a new fluorogenic reagent synthesized by our laboratory was employed as a labeling reagent, the derivatization reaction was performed in 0.10 M HEPES buffer (pH 7.4) for 30 min at 37°C. The detection of H₂O₂ was accomplished in 55 s, using a 40 mM HEPES buffer, 20% mannitol, pH 7.4, on a glass microchip. The RSDs of migration time and peak area were 1.8 and 3.7%, respectively. Method validation showed the linear response ranging from 0.50 to 50 μM with an LOD (S/N=3) of 0.20 μM (19.1 amol). The proposed method was applied to determine H₂O₂ in phorbol myristate acetate‐stimulated RAW264.7 macrophages, the concentration of H₂O₂ was found to be 1.86±0.05 μM; recoveries for macrophage samples were from 96.7 to 97.8%, within‐days and between‐days accuracies were 4.5% (n=5) and 6.8% (n=5), respectively.     

Investigation on the photophysical processes in nanosized photocatalytic thin films using planar solid-state devices

The photophysical processes for three nanosized photocatalytic oxides, titanium dioxide (TiO₂) thin film, tin dioxide (SnO₂) thin film, and layered TiO₂/SnO₂ thin film, have been examined in planar solid-state devices. It is found that, for SnO₂ thin film, the dissociation of the photogenerated excitons can take place both on the film surface and inside the film, while for TiO₂ thin film, almost all excitons dissociate on the film surface. Such a difference is proposed to account for the higher photocatalytic activity of TiO₂ over SnO₂, since it is experimentally shown that the excitons dissociate in SnO₂ thin film as efficiently as they do in TiO₂ thin film. For layered TiO₂/SnO₂ thin film, when it is illuminated by a beam of UV light, it is suggested that there exists a local electrostatic field at the SnO₂ side of the interface, mainly formed by those holes efficiently photogenerated and then localized in SnO₂ thin film. The photo-induced local electrostatic field is believed to facilitate hole–electron separation on TiO₂ thin film and therefore increase the photocatalytic activity of the layered thin film over single TiO₂ thin film.     

Synthesis and Plasmon‐Induced Charge‐Transfer Properties of Monodisperse Gold‐Doped Titania Microspheres

Functional spheres : Monodisperse gold‐doped titania spheres with tunable sizes under high concentration of titanium precursor have been synthesized by introducing trace amounts of chloroauric acid into the reaction system. Surface photovoltage, surface photocurrent, and transient photovoltage measurements (see figure) of annealed samples reveal that gold nanodots can act as both electron acceptors and donors under the illumination of different wavelengths of light.

     

Emissive or Nonemissive? A Theoretical Analysis of the Phosphorescence Efficiencies of Cyclometalated Platinum(II) Complexes

We herein report a theoretical analysis based on a density functional theory/time‐dependent density functional theory (DFT/TDDFT) approach to understand the different phosphorescence efficiencies of a family of cyclometalated platinum(II) complexes: [Pt(NCN)Cl] ( 1 ; NCN=1,3‐bis(2‐pyridyl)phenyl^?), [Pt(CNN)Cl] ( 2 ; CNN=6‐phenyl‐2,2′‐bipyridyl^?), [Pt(CNC)(CNPh)] ( 3 ; CNC=2,6‐diphenylpyridyl^2?), [Pt(R‐CNN)Cl] ( 4 ; R‐CNN=3‐(6′‐(2′′‐naphthyl)‐2′‐pyridyl)isoquinolinyl^?), and [Pt(R‐CNC)(CNPh)] ( 5 ; R‐CNC=2,6‐bis(2′‐naphthyl)pyridyl^2?). By considering both the spin–orbit coupling (SOC) and the electronic structures of these complexes at their respective optimized singlet ground (S₀) and first triplet ( ) excited states, we were able to rationalize the experimental findings that 1) 1 is a strong emitter while its isomer 2 is only weakly emissive in CH₂Cl₂ solution at room temperature; 2) although the cyclometalated ligand of 3 has a higher ligand‐field strength than that of 1 , 3 is nonemissive in CH₂Cl₂ solution at 298 K; and 3) extension of π conjugation at the lateral aryl rings of the cyclometalated ligands of 2 and 3 to give 4 and 5 , respectively, leads to increased emission quantum yields under the same conditions. We found that Jahn–Teller and pseudo‐Jahn–Teller effects are operative in complexes 2 and 3 , respectively, on going from the optimized S₀ ground state to the optimized excited state, and thus lead to large excited‐state structural distortions and hence fast nonradiative decay. Furthermore, a strong‐field ligand may push the two different occupied d orbitals so far apart that the SOC effect is small and the radiative decay rate is slow. This work is an example of electronic‐structure‐driven tuning of the phosphorescence efficiency, and the DFT/TDDFT approach is demonstrated to be a versatile tool for the design of phosphorescent materials with target characteristics.     

膜去溶-ICP-MS测定高纯CeO2中14种痕量稀土杂质分析方法研究

研究了不经基体分离, 膜去溶-ICP-MS法直接测定高纯CeO2中14种痕量稀土杂质的分析方法, 讨论了Ce基体产生的多原子离子对被测元素的质谱干扰, 并且对影响多原子离子产率的因素进行了分析, 同时建立了Pr, Gd, Tb和Yb数学校正方程. 通过使用膜去溶雾化器和优化ICP-MS参数, 消除了CeH+, CeO2+和CeO2H+产生的质谱干扰, 将CeO/Ce产率降为0.008%, 同时结合数学校正方程彻底消除了CeO+, CeOH+和CeOH2+的质谱干扰. Pr, Gd, Tb和Yb的方法测定下限分别为0.08, 0.1, 0.15和0.008 μg · g-1, 14种稀土杂质方法测定下限和为0.75 μg · g-1. 99.999%高纯CeO2实际样品测定加标回收率为96%～103%, RSD为 1.2%～4.3%.