电感耦合等离子体质谱法测定高纯稀土样品中多种非稀土杂质

研究建立了高纯稀土样品中24种非稀土杂质元素的电感耦合等离子质谱法(ICP-MS)测定方法。考察了几类典型金属样品分析中的基体效应,引入内标元素铟,有效补偿了基体效应引起的非质谱干扰。对几种在分析过程中存在质谱干扰的样品,通过分离基体进行测定。方法测定下限为1.8~390 ng.g-1,RSD为2.9%~5.4%,加标回收率为92%~107%。     

微波消解-电感耦合等离体子质谱法(ICP-MS)同时测定畜禽粪便中7种重金属元素

粪便样品干燥、研磨后,称取0.25 g样品,加入8 mL硝酸,采用微波消解方法进行前处理。采用KED模式消除质谱干扰,采用内标校正消除非质谱干扰(Ge作为Cu、Zn、Cr的内标,Bi作为Hg和Pb的内标,Rh作为As和Cd的内标),建立了可同时测定畜禽粪便中Cu、Zn、Cr、As、Cd、Pb、Hg 7种重金属元素的微波消解-电感耦合等离子体质谱法。方法线性相关系数均在0.9995以上,检出限为0.005~0.305μg/L,加标回收率为83.6%~112%,相对标准偏差为0.70%~5.6%。方法灵敏度、准确度和精密度高,实用性强,适用于同时检测畜禽粪便中多种重金属元素,对畜禽粪便的科学还田具有指导意义。     

加速溶剂萃取-气相色谱/串联质谱法测定土壤中20种有机氯农药

建立了用加速溶剂萃取法(ASE)提取、凝胶渗透色谱(GPC)净化、三重四级杆气相色谱串联质谱法(多反应监测模式,MRM)同时测定土壤中20种有机氯农药的方法。考察了不同分段时间对目标物净化效率及回收率的影响,并以消除背景干扰、提高测定灵敏度为目的,优化了串联质谱的仪器参数,确定了测定方法。当取10 g土壤时,20种有机氯农药的方法定量限在0.48~1.96μg/kg之间,实际土壤样品的加标回收率在73.7%~118%之间,相对标准偏差在2.7%~13%之间。对5份不同类型土壤进行检测。     

电感耦合等离子体原子发射光谱(ICP-AES)法测定蒙药巴特日中17种元素的含量

建立了快速、准确同时测定蒙药巴特日中多种元素含量的方法。采用电感耦合等离子体原子发射光谱(ICP-AES)法同时测定了蒙药巴特中17种常量、微量及重金属元素的含量,进行了加标回收实验,结果表明,巴特日中Ca、P、K的含量较高,富含Fe和Mg等营养元素,Pb、Cd等重金属元素均低于国家标准。相对标准偏差(RSD)在0.36%~0.86%,加标回收率为95.8%~103%。测定的实验数据准确,可靠,可用于蒙药巴特日中多种元素的同时测定。     

全自动消解电感耦合等离子体质谱仪测定环境土壤中铍钡铊银

采用HNO3-HF-HCl O_4消解体系,利用全自动消解仪优化的程序消解土样,电感耦合等离子体质谱仪(ICP-MS)碰撞气流速3.0~4.0 mL/min,以7Li,~(103)Rh,~(209)Bi作为内标,通过编辑干扰元素校正方程校正质谱干扰,建立全自动消解电感耦合等离子体质谱仪测定土壤中铍、钡、铊、银4种元素的新方法。结果表明:铍、钡、铊、银校准曲线r0.999,方法检出限在0.005~0.1μg/g之间,RSD为0.19%~2.0%,加标回收率在100.0%~109.2%,该方法用GSS-13和GSS-10标准样品验证,相对误差-3.8%~1.7%,与标准值吻合。采用实验方法对松花江河岸土壤中4种元素进行测定,并用电感耦合等离子体发射光谱法(ICP-AES)进行仪器比对,结果基本一致。     

混酸消解-电感耦合等离子体质谱法（ICP-MS） 同时测定土壤样品中10种重金属元素

建立了盐酸、硝酸、氢氟酸、高氯酸四酸消解-电感耦合等离子体质谱体系,对土壤环境样品中的铜、铅、锌、镍、镉、铬、钴、铊、锰、锑等重金属的测定进行了研究与讨论。优化了样品前处理条件和电感耦合等离子体质谱仪的相关参数,并利用内标元素45Sc、103Rh、209Bi校正土壤基体效应干扰。实验结果表明,各元素标准曲线的相关系数R均在0.9996之上,方法检出限（3σ）在0.007-0.325ug/g之间,加标回收率为92.5%-108.2%,相对标准偏差为0.2%-4.2%。研究过程中选用国家一级土壤成分分析标准物质进行质量控制,其测定值与标准值基本相符,从而为土壤中重金属元素提供了真实有效的检测依据,可用于大批量土壤中重金属元素的测定。     

电感耦合等离子体质谱(ICP-MS)法测定锰矿冶炼烟尘中多种重金属元素

为了准确测定锰矿冶炼烟尘中重金属元素的含量,为锰矿冶炼过程中监测和评价环境影响提供有力的数据支撑,采用HCl+HNO₃+HClO₄+HF消解体系对试样进行前处理,通过选用合适的内标溶液消除测定中的非质谱干扰,采用碰撞池模式和编辑校正方程消除质谱干扰,从而建立了电感耦合等离子体质谱法测定锰矿冶炼烟尘中的Cr、Ni、Cd、Tl、Pb等多种重金属元素的方法。实验结果表明,各元素标准曲线的线性相关系数均大于0.999 9,方法检出限为0.007～0.094 mg/kg,样品测定的相对标准偏差(RSD,n=11)在0.43%～4.9%,样品加标回收率为93.8%～107%。方法具有操作简便、线性范围宽、检出限低、精密度高等优点,满足锰矿冶炼烟尘中Cr、Ni、Cd、Tl、Pb等多种重金属元素同时测定的要求。     

电感耦合等离子体质谱法(ICP-MS)测定土壤中的重金属元素

采用电感耦合等离子体质谱法(ICP-MS)测定了国家标准土壤样品中的部分重金属元素(Cd,Cu,Pb,Zn,Cr,Ni,Mo)的含量,其测定值与推荐值相符,准确度符合国家标准要求。各元素方法的检出限满足要求,相对标准偏差(RSD)介于0.91%~4.3%,加标回收率介于94%~106%。方法简便快速,结果准确,可以运用于大批量地质样品中的部分重金属元素含量的同时测定。     

电感耦合等离子体质谱测定地质样品中多种元素

用电感耦合等离子体质谱(ICP-MS)测定了地质样品中多种元素。考察了测量过程中的基体效应及质谱干扰,利用In内标,补偿由于基体效应的影响所引起的测量偏差,建立校正公式校正质谱干扰。方法的检出限为0.06~250ng/L,精密度为1.7%~3.2%,加标回收率为91%~108%,方法适于批量地质样品分析。     

微波消解-电感耦合等离子体质谱(ICP-MS)法测定纳米银抗菌产品中多种微量元素

建立了微波消解-电感耦合等离子体质谱(ICP-MS)法测定4种纳米银抗菌产品中多种微量元素的分析方法。比较了湿法消解和微波消解这两种样品前处理方法对样品测定的影响,探讨了消除汞记忆效应的方法,并研究了待测元素的质谱干扰的消除。实验结果表明,采用Au(100μg/L)+HCl(2%)能较好地消除Hg的记忆效应。与湿法消解相比,微波消解可短时间消解样品并获得好的Hg回收率。在优化ICP-MS条件后,各元素线性相关系数均大于0.999。采用微波消解-ICP-MS法对样品进行加标回收,样品加标回收率在84.0%~109%,相对标准偏差在0.97%~13.2%。方法快速、简便,能够满足纳米银抗菌产品中微量元素的定量测定。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.