水杨酸在多壁碳纳米管修饰电极上的电化学行为及其测定

用循环伏安法(CV)研究了水杨酸(SA)在多壁碳纳米管修饰玻碳电极上的电化学行为,并初步探讨了反应机理.实验结果表明,水杨酸在该电极上为一个2e/H~+的完全不可逆过程.在pH=5.0的磷酸盐缓冲溶液(PBS)中,用循环伏安法在该电极上测定了水杨酸.方法线性范围为2.0×10~(-5)～1.0×10~(-3)mol/L,检出限为8.93×10~(-6)mol/L.将该电极用于药品分析,结果令人满意.     

Determination of synthetic musk compounds in indoor house dust by gas chromatography–ion trap mass spectrometry

A new method for the simultaneous determination of 11 synthetic musks and one fragrance compound in house dust was developed. The nitro musks included musk ketone (MK, 4-tert-butyl-3,5-dinitro-2,6-dimethylacetophenone), musk xylene (MX, 1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene), musk ambrette (1-tert-butyl-2-methoxy-4-methyl-3,5-dinitrobenzene) and musk moskene (1,1,3,3,5-pentamethyl-4,6-dinitroindane). The polycyclic musk compounds were 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-(γ)-2-benzopyran (HHCB), 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN), 4-acetyl-1,1-dimethyl-6-tert-butylindane, 6-acetyl-1,1,2,3,3,5-hexamethylindane, 5-acetyl-1,1,2,6-tetramethyl-3-isopropylindane, 6,7-dihydro-1,1,2,3,3-pentamethyl-4(5H)-indanon. The one macrocyclic musk was 1,4-dioxacycloheptadecane-5,17-dione. The bicyclic hydrocarbon fragrance compound (1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethylnaphthalen-2yl)ethan-1-one (OTNE) and HHCB-lactone (4,6,6,7,8,8-hexamethyl-1H,3H,4H,6H,7H, 8H-indeno[5,6-c]pyran-1-one), a degradation product of HHCB, were also analysed. NIST SRM 2781 (domestic sludge) and SRM 2585 (organic contaminants in house dust) were analysed for these target compounds. The method was applied for the analysis of 49 paired samples collected using two vacuum sampling methods: a sample of fresh or "active" dust (FD) collected using a Pullman-Holt vacuum sampler, and a household dust (HD) sample taken from the participants' vacuum cleaners. Method detection limits and recoveries ranged from 12 to 48?ng/g and 54 to 117?%, respectively. AHTN, HHCB, OTNE and HHCB-lactone were detected in all samples, with median concentrations of 552, 676, 252 and 453?ng/g for FD samples, respectively; and 405, 992, 212 and 492?ng/g for HD samples, respectively. MX and MK were detected with high frequencies but with much lower concentrations. The two sampling methods produced comparable results for the target analytes. Widely scattered concentration levels were observed for target analytes from this set of 49 house dust samples, suggesting a wide variability in Canadian household exposure to synthetic musks.     

Simultaneous HPLC Determination of Four Key Metabolites in the Metabolic Pathway for Production of 1,3-Propanediol from Glycerol

A high-performance liquid chromatographic (HPLC) method with refractive-index detection has been developed for simultaneous analysis of glycerol, dihydroxyacetone (DHA), 3-hydroxypropionaldehyde (3-HPA), and 1,3-propanediol (1,3-PD), four key substances in the metabolic pathway for production of 1,3-PD from glycerol by microorganism fermentation. The compounds were separated on a 300 mm × 7.8 mm ion-exclusion column with a 65:35 (v/v) mixture of deionized water and acetonitrile, containing 0.0005 M H₂SO₄, as mobile phase. The flow rate was 0.5 mL min^?1. Under these conditions the retention times of 3-HPA, DHA, glycerol, and 1,3-PD were 6.87, 14.63, 16.37, and 18.50 min, respectively. Relative standard deviations and average recoveries were between 0.42 and 0.63% and between 96.7 and 103.1%, respectively; detection limits were between 0.017 and 0.038 g L^?1. The method enabled separation of these compounds.     

Self assembly of two novel three-dimensional supramolecular networks with blue photoluminescence

Two novel photoluminescent coordination polymers of the formula [Cd(Haip)₂(H₂O)₂] · 2H₂O (1) and [Zn(aip)(atz)] · 3H₂O (2) (H₂aip = 5-aminoisophthalic acid; atz = 3-amino-1,2,4-triazole) have been synthesized through the self-assembly of metal(II) ions with H₂aip and N-containing ligands [2-amino-5-mercapto-1,3,4-thiadiazole for 1 and 3-amino-1,2,4-triazole for 2, respectively] in the presence of NaOH. These complexes were characterized by FT-IR spectroscopy, thermogravimetric analysis (TG), elemental analysis and X-ray analysis. X-ray crystallographic studies of the complexes reveal that 1 is a first example where only one carboxylate group of the H₂aip ligand participates in coordination with the metal(II) ion and it exhibits a two-dimensional framework which further assembles into a three-dimensional supramolecular network via interlayer π–π stacking interactions and strong hydrogen bonds, while 2 exhibits a two-dimensional porous architecture. The extensively strong hydrogen bonds and interlayer π–π stacking interactions in 2 lead to the formation of a three-dimensional supramolecular network. Photoluminescence properties of the compounds 1 and 2 have been examined in the solid state at room temperature. These compounds have been found to exhibit blue photoluminescence and may be good candidates for photoactive materials.     

Improving MCM‐41 as a Nitrosamines Trap through a One‐Pot Synthesis

Copper oxide was incorporated into MCM‐41 by a one‐pot synthesis under acidic conditions to prepare a new mesoporous nitrosamines trap for protection of the environment. The resulting composites were characterized by XRD, N₂ adsorption–desorption, and H₂ temperature‐programmed reduction techniques, and their adsorption capabilities were assessed in the gaseous adsorption of N‐nitrosopyrrolidine (NPYR). The adsorption isotherms were consistent with the Freundlich equation. The copper salt was deposited onto MCM‐41 during the evaporation stage and was fixed on the host in the calcination process that followed. MCM‐41 was able to capture NPYR in air below 373 K but not at 453 K. Loading of copper oxide on MCM‐41 greatly improved its adsorption capability at elevated temperatures. The influence of the incorporation of copper into MCM‐41 samples and the adsorption behavior of these samples are discussed in detail.     

Enantioselective iodolactonization catalyzed by chiral quaternary ammonium salts derived from cinchonidine

Chiral quaternary ammonium salts derived from cinchonidine have been applied to catalyze the stereoselective iodolactonizations of trans-5-aryl-4-pentenoic acids leading to a mixture of two regioselectively iodolactonized products with fair to excellent yield (37-98%) and moderate enantioselectivity (exo = 42.0% ee, endo = 31.0% ee) under mild conditions. This work is the first example of asymmetric iodolactonization reaction in the presence of less than a stoichiometric amount of chiral reagent.     

基于双功能单体的磁性双酚A印迹聚合物的制备及应用

以二氧化硅包覆的四氧化三铁为载体,双酚A(BPA)为模板分子,β-环糊精和4-乙烯基吡啶为二元功能单体,采用热聚合方法制备了对双酚A具有特异吸附性能的磁性印迹复合材料(mag-MIPs).采用透射电子显微镜(TEM)、傅里叶变换红外光谱(FTIR)和振动样品磁强计(VSM)对该印迹复合材料进行了表征,并结合磁固相萃取(M-SPE)技术和高效液相色谱(HPLC)研究了其对双酚A的吸附行为,结果表明该印迹复合材料对双酚A具有良好的选择吸附能力.液相色谱检测结果表明,该磁性印迹复合材料可用于环境水样中双酚A的快速分离富集,回收率为90.51%~98.21%.     

由纳米晶前驱体组装有序介孔silicalite-1分子筛

采用两步法将不同尺寸的silicalite-1分子筛纳米晶种通过自组装合成了一系列有序介孔silicalite-1分子筛。首先将强碱性的silicalite-1前驱体分别加热不同时间得到纳米晶种,然后在类似合成SBA-15的强酸性条件下组装成有序的介孔材料。合成条件的剧烈变化阻止了分子筛晶种的继续长大,并在三嵌段共聚物模板的诱导下组装成有序介孔材料。这种“自下而上”的方法制备有序介孔分子筛同时包含微孔和介孔。氮气吸脱附结果表明所制备的介孔分子筛材料均表现了很大的比表面积(730 m2/g以上)。     

中美化学教科书中生涯教育思想的渗透比较与分析

对美国高中《化学概念与应用》和我国高中课程标准人教版、鲁科版、苏教版共4种化学教材里生涯教育内容进行比较,从功能定位、目标定向、对象呈现3个维度对中美2国的价值取向进行了分析,为我国高中化学教科书中生涯教育栏目的设置提出建议.