On-line pretreatment and determination of Pb, Cu and Cd at the μg l level in drinking water by chelation ion chromatography

A novel, highly sensitive method for the simultaneous separation and determination of lead, copper, cadmium and other transition metals in drinking water was achieved by on-line sample pretreatment of chelation ion chromatography. Manganese, which coeluted with cadmium, was oxidized to permanganate by ammonium persulfate before injection. Permanganate, with bulk quantity of alkali, alkaline earth metals, iron and aluminum, was eliminated by pyrophosphoric acid–ammonium acetate buffer solution (pH 5.5), while retaining heavy and transition metals on a selective chelating resin (MetPac CC-1 column). Then, they were disabsorbed and transferred to a sulfonated cation exchanger (TMC-1 column). Finally, the concentrated trace metals were separated on a bifunctional ion-exchange column (CS5A) by a concentration gradient of oxalic acid and sodium nitrate eluents, coupled with post-column spectrophotometric detection with 2-[(5-bromo-2-pyridyl)azo]-5-diethylaminophenol (5-Br-PADAP) at 560 nm. The separation and color-development conditions were optimized. The detection limits for the method (signal-to-noise ratio=3:1) were at or below the μg l⁻¹ level. The results of drinking water analyses were satisfactory.     

TBP萃淋树脂吸附钪的性能研究及应用

本文采用静动态两种方法较系统地研究了TBP草淋树脂在高氟酸介质中吸附钪的性能，并用自己设计的减压微色谱柱考察了共存离子的萃取色谱行为，选择了分离微量钪的最佳条件，获得了良好的分离效果，用于标准矿样中微量机的测定，分析结果与标准值相近。     

基于3,6-二肼基-1,2,4,5-四嗪的两种高氮含能离子盐

本文通过3,6-二肼基-1,2,4,5-四嗪(DHT)分别与高氯酸和硝酸反应得到2种高氮含能离子盐,并通过X-射线单晶衍射技术对它们的结构进行了表征。(DHT)(NO₃)₂(1)属于单斜晶系,C2/c空间群,晶胞参数:a=1.3000(6)nm,b=0.8349(3)nm,c=1.0187(5)nm,β=118.89(5)°,Z=4;(DHT)(ClO₄)₂(2)属于正交晶系,P2₁2₁2空间群,晶胞参数:a=0.9804(4)nm,b=1.0747(4)nm,c=0.5325(2)nm,Z=2。采用DSC和TG-DTG技术研究了这两种含能离子盐的热分解机理,并对这两种含能离子盐的非等温动力学、爆热及感度进行了测试分析。研究表明这两种含能离子盐在敏感型含能材料领域具有潜在的应用前景。     

H_2TPP与AgNO_3在乙醇中的光反应

用紫外可见吸收光谱研究了 5,10 ,15,2 0 -四苯基卟啉 (H2 TPP)的乙醇溶液与AgNO3的乙醇溶液混合后 ,在光照条件下的化学反应。谱图显示H2 TPP发生络合反应 ,生成其二价银络合物Ag(Ⅱ )TPP。银胶能加快该反应的速度。     

Conversion of quassinoids for enhancement of inhibitory effect against Epstein-Barr virus early antigen activation. Introduction of lipophilic side chain and esterification of diosphenol

Introduction of a senecioyl group into shinjulactones B and C, and esterification of the diosphenol moiety in brusatol and brucein A enhanced inhibitory effect against Epstein-Barr virus early antigen activation.     

聚合物纳米微粒静电组装行为及其表征

使用2,2′-偶氮二异丁基脒二盐酸盐自由基引发剂,改变甲基丙烯酰氧乙基十六烷基二甲基溴化铵阳离子功能单体的量与苯乙烯进行乳液聚合获得不同粒径的阳离子乳胶粒,使用十二烷基硫酸钠为乳化剂和过硫酸钾为引发剂制备阴离子聚合物乳胶粒.采用基于静电相互作用的异凝聚法将以上2种带有相反电荷的乳胶粒组装,获得了表面粗糙程度不同的复合微粒.对异凝聚过程中复合液透光率和微粒大小及分布进行跟踪测试,并用透射电子显微镜表征了阳离子微粒、阴离子微粒以及复合微粒的形态和大小.结果表明,在一定范围内可以通过控制阴离子乳胶粒与阳离子乳胶粒的复合比例改变单个复合微粒表面阳离子小微粒的数目.     

{[Eu(ox)(H2O)4]·[CuBr(2‐pzc)2]·4H2O}: Hydrogen Bonding Directed Assembly to Supramolecular Network

A new 3d–4f heterometallic coordination framework, {[Eu(ox)(H₂O)₄] · [CuBr(2‐pzc)₂] · 4H₂O} ( 1 ) [ox = oxalate; 2‐pzc = pyrazine‐2‐carboxylate] was synthesized and characterized by elemental analysis, IR spectroscopy and thermal analysis, as well as single‐crystal X‐ray diffraction. Complex 1 represents one 3D supramolecular heterometallic coordination framework that is assembled from rare lanthanide‐ox anionic chains and CuBr(2‐pzc)₂ cationic units through hydrogen bonds.     

A Dual‐Phase Ceramic Membrane with Extremely High H2 Permeation Flux Prepared by Autoseparation of a Ceramic Precursor

A novel concept for the preparation of multiphase composite ceramics based on demixing of a single ceramic precursor has been developed and used for the synthesis of a dual‐phase H₂‐permeable ceramic membrane. The precursor BaCe_0.5Fe_0.5O_3?δ decomposes on calcination at 1370 °C for 10 h into two thermodynamically stable oxides with perovskite structures: the cerium‐rich oxide BaCe_0.85Fe_0.15O_3?δ (BCF8515) and the iron‐rich oxide BaCe_0.15Fe_0.85O_3?δ (BCF1585), 50 mol % each. In the resulting dual‐phase material, the orthorhombic perovskite BCF8515 acts as the main proton conductor and the cubic perovskite BCF1585 as the main electron conductor. The dual‐phase membrane shows an extremely high H₂ permeation flux of 0.76 mL min^?1 cm^?2 at 950 °C with 1.0 mm thickness. This auto‐demixing concept should be applicable to the synthesis of other ionic‐electronic conducting ceramics.     

离子色谱-质谱联用技术测定污泥样品中的痕量高氯酸盐

建立了离子色谱-质谱联用技术测定活性污泥样品中高氯酸盐的分析方法。以高容量、强亲水性的IonPacAS20(2mm)阴离子交换柱为分析柱,EGC在线产生等浓度KOH为淋洗液,淋洗液经抑制成水后将样品带入质谱检测。ESI-MS-MS以多元反应监测模式监控100.8/84.9、98.8/66.9、100.8/68.9和98.8/82.9离子对,以98.8/82.9离子对的峰面积进行定量。该方法对高氯酸盐的检出限(S/N=3)为0.01μg/L,高氯酸盐在0.05~100μg/L浓度范围内具有良好的线性,线性相关系数r=0.9988。0.2μg/L的标准溶液重复进样9次,高氯酸盐峰面积的相对标准偏差(RSD)为2.3%。运用该方法测定采自不同地区的活性污泥样品中的高氯酸盐,并对样品加标回收,得回收率在88.5%~102.2%之间。