气相色谱-三重四极杆串联质谱稳定同位素稀释法测定被动吸烟儿童尿液中的可丁宁

建立了被动吸烟儿童尿液中可丁宁的气相色谱-三重四极杆串联质谱（GC-MS/MS）稳定同位素稀释测定方法。尿液经过三氯甲烷提取、净化,采用气相色谱-三重四极杆串联质谱多反应监测（MRM）模式测定,以可丁宁-d₃稳定同位素为内标,定量测定和确证被动吸烟儿童尿液中的可丁宁;在0.1~10 μg/L可丁宁质量浓度范围内方法的线性关系良好,相关系数r>0.998;空白尿液中添加可丁宁0.1、1.0和10 μg/L,回收率为79.2%~112.8%,相对标准偏差在2.1%~5.8%之间;方法定量限达到0.1 μg/L。该方法准确、灵敏、快速,适用于家庭被动吸烟儿童尿液中可丁宁的测定。     

新型3-芳基香豆素类化合物的合成及其抗肿瘤活性

以芳基乙酸和取代邻羟基苯甲醛为起始原料,经Perkin缩合和关环反应合成了16个新型的3-芳基香豆素类化合物(3a~4h),其结构经1H NMR,IR和EI-MS表征。采用MTT法测定了3和4对人鼻咽癌细胞株(KB)、人气道平滑肌细胞株(KV)、人乳腺癌细胞株(MCF-7)、人乳腺癌多药耐药细胞株(MCF-7/ADR)的细胞毒性。结果表明:部分化合物表现出较强的细胞增殖抑制活性,其中7,8-二乙酰氧基-3-(4'-甲氧基苯基)香豆素(3e)对KB细胞的活性最强(IC505.88μmol·L-1)。     

含N-乙酰化肝素寡糖的制备及序列分析

建立了含N-乙酰化肝素寡糖的分离提纯及其序列结构分析方法.首先应用肝素酶Ⅰ深度酶解低分子量肝素来富集含N-乙酰化结构寡糖,通过Bio-Gel P10凝胶色谱法分离制备了包括二糖至十四糖的系列肝素寡糖粗样品,ProPac PA-1强阴离子高效液相色谱(SAX-HPLC)等方法对粗样品进一步分离,提纯得到4种六糖和3种八糖片段.其次应用肝素酶Ⅰ,Ⅱ和Ⅲ复合酶解与HPLC法分析各纯化寡糖的二糖组分,并结合肝素酶Ⅰ底物特异性,初步推断4种六糖和3种八糖的序列结构.在寡糖的糖链两端均含有N-硫酸化二糖,而N-乙酰化二糖分布在糖链当中.应用电喷雾离子阱-飞行时间质谱(ESI-IT-TOF-MS)在负离子模式下进一步表征寡糖并分析其裂解规律.结果表明,各寡糖中均出现大量因SO32-丢失形成的碎片离子峰,六糖中主要有双电荷和三电荷碎片离子峰;在八糖中出现了一系列从双电荷至五电荷的离子峰.各寡糖的双电荷离子峰质荷比进一步确定了上述寡糖的序列结构.六糖的裂解规律表明,裂解主要存在于糖苷键,N-乙酰葡糖胺和糖醛酸上的裂解方式分别为0,2X和0,2Z.本研究提供了切实有效的分离、分析未知结构肝素寡糖序列的新方法.     

改性活性炭负载氯化铁催化氧杂蒽衍生物的合成

制备了一种新型改性活性炭负载FeCl₃催化剂(MAC-FeCl₃),并通过红外光谱及等离子体发射光谱等技术手段对其进行了表征。 在MAC-FeCl₃催化下,β-萘酚与醛在PEG200中,于120 ℃反应60~120 min,合成了一系列氧杂蒽类衍生物,收率为79%~93%。 该方法操作简单、产率高、环境友好。 制备的催化剂性能稳定,使用4次仍保持较高活性。     

2-羟丙基-β-环糊精与二茂铁衍生物超分子胶束通过氧化还原响应控制药物释放

合成了新型的具有长链的二茂铁衍生物(P-Fc),并将其包络在2-羟丙基-β-环糊精(HP-β-CD)的空腔中,自组装形成超分子囊泡,并通过FTIR、1 HNMR、SEM和CV曲线对其进行结构形貌表征;分别以罗丹明6G(R6G)、盐酸阿霉素(DOX)作为药物,实现了R6G、DOX在囊泡中的成功装载。并通过加入氧化剂,将二茂铁氧化成二茂铁盐,将囊泡破坏,实现了 R6G 和 DOX 的快速定向释放,其药物装载量分别为6.89和39.06μg/mg,最大释放率分别为73.7%和88.2%。     

气相色谱-质谱法测定水中25种挥发性有机物及其在污水厂应急溯源中的应用

采用吹扫捕集-气相色谱-质谱法测定水中25种挥发性有机物的含量,并研究了其在污水厂应急溯源中的应用。25种挥发性有机物在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3.143s)在0.6~5.0μg·L-1之间。以空白样品为基体进行加标回收试验,所得回收率在91.6%~102%之间,测定值的相对标准偏差(n=6)在2.7%~4.6%之间。在一起污水厂冲击案例中,通过污水管网采样及污水样品分析,确定污染因子二氯甲烷,并根据二氯甲烷浓度变化快速锁定污染源头,确保污水厂出口水质达标。     

Bi_2O_3掺杂对Ag(Nb_(0.8)Ta_(0.2))O_3陶瓷结构和介电性能的影响(英文)

本文研究了Bi2O3掺杂对Ag(Nb0.8Ta0.2)O3陶瓷的结构和介电性能的影响。X射线衍射(XRD)结果表明,Bi2O3的掺杂可以使陶瓷中Ag+被还原并析出,且银析出的量随Bi2O3掺杂量的增加而不断增加,这可能源自于Bi3+对Ag+的取代。在一定范围内增大Bi2O3掺杂量可提高Ag(Nb0.8Ta0.2)O3陶瓷的室温介电常数,降低介电损耗,并使温度系数向负值方向移动。当Bi2O3的掺杂量约为3.5wt%时,样品具有较大的介电常数(ε=672)和较小的介电损耗(tanδ=7.3×10-4)。     

Electric Field-driven Acid-base Transformation: Proton Transfer from Acid(HBr/HF) to Base(NH3/H2O)

The proton-transfer between ammonia/water and HF/HBr without and with the stimulus of external electric fields(E_ext) was investigated with the ab initio calculations. When external electric field is applied, the proton transfer occurs, resulting in ion-paired H₄N⁺X^- and H₃O⁺X^-(X=Br and F) from hydrogen-bonded complexes in view of the great changes of geometrical structures, dipole moments, frontier molecular orbitals and potential energy surfaces in the critical external electric fields(E_c) of 1.131×107 V/cm for H₃N-HBr, 1.378×108 V/cm for H₃N-HF, 9.358×107 V/cm for H₂O-HBr and 2.304×108 V/cm for H₂O-HF, respectively. Furthermore, one or three excess electrons can trigger the proton transfer from H₃N-HBr and H₃N-HF to H₄N⁺Br^- and H₄N⁺F^-, while two and four excess electrons can induce the proton transfer from H₂O-HBr and H₂O-HF to H₃O⁺Br^- and H₃O⁺F^-, respectively. Compared with that of the analogous NH₃/H₂O-HCl systems, the strength of E_c of proton transfer increases from HBr to HCl and HF for either H₃N-HX or H₂O-HX series, which is understandable by the fact that the acidity sequence is HBr>HCl>HF. And the larger of acidity of conjugated acid, the smaller of needed E_c. On the other hand, the E_c for the systems of NH₃ with a stronger basicity is generally smaller than that of H₂O systems for the same conjugated acid.     

Ionic Liquid-assisted Formation of Lanthanide Metal-organic Framework Nano/Microrods for Superefficient Removal of Congo Red

New lanthanide metal-organic framework(MOF) nano/microrods, [C₄mim]Cl-Eu-MOF, [C₈mim]Cl-Eu- MOF and [C₁₂mim]Cl-Eu-MOF, were conveniently synthesized via an ionic liquid-assisted hydrothermal method and characterized by means of powder X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), thermogravimetric analysis(TG) and transmission electron microscopy(TEM). The obtained nano/microrods with low surface areas were efficient for the removal of Congo red(CR) from aqueous solutions. Under the optimum conditions, [C₄mim]Cl-Eu-MOF with a specific surface area of 5.1 m²/g exhibited an ultrahigh adsorption capacity of 2606 mg/g toward CR. Notably, the adsorption efficiency of [C₄mim]Cl-Eu-MOF for CR via nano/microscale stacking can be directly demonstrated by TEM. In-depth understanding of CR removal by [C₄mim]Cl-Eu-MOF nano/microrods was also supported by FTIR, Raman spectroscopy and zeta potential analyses.     

Asymmetric Synthesis of Furo[3,4‐b]indoles by Catalytic [3+2] Cycloaddition of Indoles with Epoxides

A highly efficient N,N′‐dioxide–Ni^II catalyst system for the catalytic [3+2] cycloaddition of indoles with epoxides through C?C cleavage of oxiranes was accomplished under mild conditions. It provided a promising approach for chiral furo[3,4‐b]indoles in up to 98 % yield with up to 91 % enantiomeric excess (ee) and >95:5 diastereomeric ratio (d.r.).