Au@ZrO2空心纳米微球的制备及其催化性质

以Stober法合成了不同粒径的SiO₂微球。以这些SiO₂微球为硬模板,通过ZrOCl₂前驱体吸附和水解制备得到了ZrO₂@SiO₂复合物,然后用HF溶解去除二氧化硅模板剂,制备得到ZrO₂空心球。以ZrO₂空心球为载体,采用沉积-沉淀法（DP）合成了Au@ZrO₂纳米空心微球。考察了Au@ZrO₂纳米空心微球在对硝基苯胺还原反应中的催化性能。研究结果表明,所合成的SiO₂微球粒径大小均一、形状规则、分散性好;ZrO₂空心微球大小及比表面积可以通过硬模板SiO₂微球粒径进行有效控制;与Au@ZrO₂实心微球相比,Au@ZrO₂空心微球在对硝基苯胺还原反应中表现出良好的催化性能,当反应温度为45℃、反应7 min时,对硝基苯胺能够完全转化为对苯二胺。     

运用表面增强拉曼散射(SERS)和密度泛函数理论(DFT)模拟计算研究对硝基苯胺在金纳米颗粒表面吸附行为

在沉积金纳米颗粒的干燥滤纸上进行对硝基苯胺的表面增强拉曼散射(SERS)光谱研究,并与对硝基苯胺在金胶水溶液中的表面增强拉曼散射(SERS)光谱相比,分子拉曼光谱发生了很大变化。同时利用DFT理论计算对硝基苯胺在金胶颗粒上的吸附行为的拉曼光谱。DFT理论模拟计算和FI-Raman实验分析都表明这种变化源于对硝基苯胺的不同吸附方式。SERS和DFT结合研究分子的吸附是一种有效的技术。     

Effect of reaction conditions on the product distribution in the liquid-phase acid-catalyzed etherification of 2-naphthol with methanol

Summary Bi-doped TiO₂photocatalysts have been prepared by a sol-gel method. The samples were examined by the methods of XRD, HRTEM and XPS. The photocatalytic activity of the catalysts was evaluated through the photocatalytic oxidation of p-nitroaniline (NO₂C₆H₄NH₂) in air.     

Regional phospholipid analysis of porcine lens membranes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) to the qualitative and quantitative analysis of most mammalian phospholipid (PL) classes was demonstrated in a crude extract of porcine lens membranes. When 2,5-dihydroxybenzoic acid (DHB) was used as the matrix, positive-ion spectra allowed the accurate quantification of phosphatidylcholines (PCs) and sphingomyelins (SMs). Other PLs such as phosphatidylethanolamines (PEs), phosphatidylethanolamine plasmalogens (PEps), phosphatidylethanolamine ethers (PEes) and phosphatidylserines (PSs), could also be detected, but their lower ionization efficiency led to negative errors in their quantification. Despite this limitation, it was possible to determine relative changes among PLs extracted from cortical and nuclear regions. Negative-ion spectra were acquired with the use of p-nitroaniline (PNA) as the matrix. Because neither PCs nor SMs produce negative ions, other PL classes can be analyzed selectively. The absolute quantification of the various PL classes detectable in negative-ion spectra was also affected by differences in ionization efficiencies. However, the trends in compositional changes between cortical and nuclear-fiber PLs were in agreement with those obtained by (31)P NMR spectroscopy. MALDI-TOFMS also offers the possibility of studying variations in the acyl-chain distribution of the various species comprising each PL class. For porcine lenses, PCs, PEs and phosphatidylinositols (PIs) exhibited the greatest depletions in going from cortical to nuclear membranes. Among their individual species, those with two or more sites of unsaturation suffered the most significant reduction.     

一种测定六价铬的新方法

基于六价铬在稀盐酸介质中氧化盐酸羟胺产生亚硝酸根 ,而亚硝酸根可使对硝基苯胺重氮化并与α -萘胺偶联产生红色偶氮染料 ,提出了分光光度法测定六价铬的新方法。在最佳实验条件下 ,六价铬的浓度在0～ 5 0 μg/2 5mL内服从比耳定律 ,其线性相关系数γ为 0 .9990 ,表观摩尔吸光度ε51 0 为 2 .48× 1 0 4 L·mol- 1 ·cm- 1 。所拟方法用于水样中微量铬的测定 ,结果满意     

对硝基苯胺与牛血清白蛋白的相互作用研究

用荧光光谱和质谱研究了对硝基苯胺(PNA)与牛血清白蛋白(BSA)的相互作用.结果表明,对硝基苯胺能与BSA相结合,结合后对硝基苯胺的ESI-MS选择正离子峰明显减弱,并有规律地猝灭BSA的内源荧光,其机理属静态猝灭过程.实验获得了不同温度下,对硝基苯胺与BSA作用的结合常数和热力学参数,根据所得结果可推断对硝基苯胺与BSA的主要作用力为疏水作用力.由Frster非辐射能量转移理论计算得出了对硝基苯胺与BSA结合位置的距离.采用同步荧光研究发现,对硝基苯胺能进入BSA的疏水区,从而对BSA的构象产生一定的影响,这与对硝基苯胺的生物毒性有关.     

Alternative approaches for the detection of various phospholipid classes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The detection of phospholipids (PLs) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was demonstrated nearly a decade ago. However, its use as a conventional tool for PL analysis has been hindered by ambiguities in peak assignments caused by spectral overlaps and difficulties in the detection of some PL classes when analytes with positively charged head groups, such as sphingomyelins (SMs) and phosphatidylcholines (PCs) are present. In this work, either a strong cation-exchange resin or CsCl crystals were added directly to the PL samples to reduce spectral complexity and enhance sensitivity. The quantitative exchange resulted in virtually only protonated or Cs+ adducts. To alleviate difficulties in the detection and identification of PL classes with ionization efficiencies lower than those of SMs and PCs, improvements in the sensitivity of negative-ion mass spectra were sought. For this purpose, several neutral and basic matrices were tried. Among them, p-nitroaniline (PNA) proved to be an advantageous alternative to the use of 2,5-dihydroxybenzoic acid (DHB), the most commonly used matrix in PL analysis. Because of its lower acidity, PNA increased the relative amount of deprotonated species and improved the sensitivity of negative-ion mass spectra. It was possible to confirm peak assignments for PL classes that normally give weak signals when DHB is used. Noteworthy is the detection (in both positive and negative modes) and conclusive identification of species in natural mixtures of phosphatidylethanolamines (PEs) and PE plasmalogens (PEps). PNA allowed the identification of PEs and PEps even in mixtures containing SMs and PCs. Although some cations related to PCs and PEs overlapped in positive-ion spectra, these interferences were eliminated in the negative mode as only the deprotonated forms of PEs and PEps were detectable and those of SMs and PCs were absent owing to their neutrality.     

Au@ZrO_2空心纳米微球的制备及其催化性质

以Stober法合成了不同粒径的SiO_2微球。以这些SiO_2微球为硬模板,通过ZrOCl_2前驱体吸附和水解制备得到了ZrO_2@SiO_2复合物,然后用HF溶解去除二氧化硅模板剂,制备得到ZrO_2空心球。以ZrO_2空心球为载体,采用沉积-沉淀法(DP)合成了Au@ZrO_2纳米空心微球。考察了Au@ZrO_2纳米空心微球在对硝基苯胺还原反应中的催化性能。研究结果表明,所合成的SiO_2微球粒径大小均一、形状规则、分散性好;ZrO_2空心微球大小及比表面积可以通过硬模板SiO_2微球粒径进行有效控制;与Au@ZrO_2实心微球相比,Au@ZrO_2空心微球在对硝基苯胺还原反应中表现出良好的催化性能,当反应温度为45℃、反应7 min时,对硝基苯胺能够完全转化为对苯二胺。     

α-呋喃甲醛缩对硝基苯胺对Hg2+的识别研究

设计合成了荧光传感分子α-呋喃甲醛缩对硝基苯胺(FFNA),通过红外(IR)光谱和核磁共振谱(1H NMR)表征了其结构.并应用荧光光谱研究其在水中对过渡金属离子的响应.结果表明,FFNA的荧光发射光谱对Hg2+表现出高的选择性响应,对Zn2+、Ni2+和Cd2+等金属离子响应则很弱;初步探讨了受体分子与Hg2+结合模式与荧光猝灭原因.     

大孔树脂对对硝基苯胺的吸附行为及其应用研究

研究了溶液中无机盐、pH值对氨基修饰超高交联大孔树脂NDA-99、氧修饰超高交联大孔树脂NDA-150和大孔树脂XAD-4吸附对硝基苯胺的影响。结果表明,无机盐对吸附影响不大;NDA-99、NDA-150在中性范围吸附量最大,XAD-4的吸附量随pH增大而增大;3种树脂的吸附等温线都能很好的利用Freundlich方程进行拟合,吸附皆为放热反应且为优惠吸附;3种树脂的饱和吸附量大小依次为NDA-150>NDA-99>XAD-4。依据上述结论,采用NDA-150处理对硝基苯胺生产母液废水,每批次处理量为40BV,废水中对硝基苯胺浓度由2130mg/L降至9.6mg/L,去除率达99.5%,吸附后的树脂采用95%的乙醇可完全再生,高浓度对硝基苯胺乙醇再生溶液经蒸馏可回收对硝基苯胺和脱附剂,实现了废水治理与资源化的统一。