电感耦合等离子体质谱测定高纯金属钐中25种杂质元素

研究建立了电感耦合等离子体质谱(ICP—MS)测定高纯金属钐中14种稀土及11种非稀土杂质的测定方法。考察了钐基体对杂质元素测定的各种干扰影响。对无干扰的杂质元素,采取了直接测量的方式;对有干扰的元素(Nd、Eu、Dy、Ho、Er、Tm),采用标准加入法的方式进行测定。选择内标元素Sc和Cs,有效补偿了由于基体效应带来的测量偏差。方法的检出限为0．012～83μg／L．加标回收率为88．6％～108．0％．测定精密度(RSD)为0．55％～2．53％,方法可满足99．9％纯度的金属钐中朵质元素的分析测定。     

等离子体质谱多内标法测定金属铒中多种痕量元素

本方法采用ICP—MS法同时测定高纯金属铒中14个稀土元素和15种非稀土元素杂质，确定了合适的样品稀释浓度，采用Sc、In、Cs、Tl4个内标，杂质元素的检出限在0．04～16μg／g之间，样品的加标回收率在86％～105％之间，能够满足4N金属铒产品的检测需求。     

电感耦合等离子体质谱法测定农产品土壤中痕量稀土元素

建立了电感耦合等离子体质谱法（ICP-MS）测定农产品土壤中15个稀土元素的分析方法．研究了溶样体系用量、标准溶液配制、质谱干扰、内标元素的选择．采用HNO3-HF—H2O2体系电热板溶解样品,稀土元素的溶出率较高．用ICP—MS同时测定土壤中的钇、镧、铈、镨、钕、钐、铕、钆、铽、镝、钬、铒、铥、镱、镥．以Rh、Re双内标在线校正,有效地降低了信号漂移对分析结果的影响．方法检出限为0．0012—0．0071ng／mL．对实际样品进行连续7次测定,方法精密度为0．2％～4．7％,回收率为97％-114％．经国家标准物质验证,结果与标准值相符．方法弥补了微波消解法的不足,且快速、准确,适合于大批量土壤样品分析．     

高纯金属镱中杂质元素的电感耦合等离子体质谱法测定

利用电感耦合等离子体质谱仪(ICP—MS)直接测定了金属镱中除Tm、Lu外其他稀土及非稀土杂质元素;通过P507萃淋树脂色层柱,分离绝大部分Yb基体,避免了基体元素对Tm、Lu的测定干扰?定量加入内标元素Sc、Cs,有效克服了基体效应所带来的偏差。稀土杂质元素的检出限0．010～0．032μg／g,非稀土杂质元素的检出限为0.12～5．0μg／g。加标回收率为83％～105％。方法适用于纯度为99．99％～99．999％的高纯金属镱产品中杂质元素的测定。     

电感耦合等离子体质谱法测定水处理材料浸泡液中微量元素

提出了电感耦合等离子体质谱（ICP—MS）法测定水处理材料浸泡液中微量锰、铜、锌、镉、银、铅的方法。按国家标准GB／T5750所述方法对水处理材料进行浸泡,以铟作内标物质,用ICP-MS同时测定浸泡液中6种元素。上述6元素的检出限在0．006～0．252μg·L^-1之间,回收率在85％-107％之间。     

激光剥蚀-电感耦合等离子体质谱法测定土壤中15种微量元素

在土壤标准样品中加入内标元素铼,将其压片后直接进样,将激光聚焦在样品表面下100μm,在以下条件下进行激光剥蚀(LA):(1)剥蚀载气氦气流量为600mL·min-1;(2)剥蚀光斑直径为110μm;(3)剥蚀速率为50μm·s-1。剥蚀后形成的气溶胶进入电感耦合等离子体质谱仪(ICP-MS),对其中15种微量元素(铍、钒、铬、钴、镍、铜、锌、镓、砷、镉、锡、锑、铊、铅、铋)进行测定。采用标准加入法,通过校准曲线外推得到各目标元素的含量。检出限(3s)为0.01～0.08μg·g~(-1);用此方法分析了2个土壤标准样品(GSS-3和GSS-14),除铍、锑和镉,其他元素所得测定值均在认定值的允许不确定度范围内,且相对误差(RE)均不超过10%;对土壤标准样品(GSS-14)重复测定5次,15种元素测定值的相对标准偏差(n=5)均在10%以内。     

电感耦合等离子体质谱法测定人尸体10种器官组织样品中15种痕量稀土元素的研究

采用ICP MS法对人尸体 1 0种器官组织样品中痕量稀土元素测定进行了研究 ,选择了最佳仪器工作参数 ,用铑 (Rh)为内标元素补偿基体效应和灵敏度漂移 ,检出限为 0 .0 0 5 ( 89Y)～ 0 .0 2 3( 172 Yb)ng mL ,肝样品的加标回收率为 81 %～ 1 1 8% ,相对标准偏差为 1 .6%～ 1 4%。在严格质量控制的基础上用HNO3 HClO4混合酸消解样品 ,不须分离富集 ,直接对人尸体的肺、肝、骨、甲状腺、小肠、胃、肌肉、肾、脾和心中 1 5种痕量稀土元素进行测定。     

稀土化合物中Cl-的ICP-MS测定

研究了用ICP－MS法测定稀土化合物中Cl^-1。对分析线，内标元素和基体浓度进行了合理选择。方法的加标回收率在80％－125％。相对标准偏差在6．24％－14．70％，测定下限为0．005％。     

电感耦合等离子体原子发射光谱（ICP-AES）法测定高铁土壤中Al

采用碱熔再酸化分解样品,电感耦合等离子体原子发射光谱法(ICP—AES)测定高铁土壤中Al。通过逐级扩大线性范围的方式,选取测定高含量Al的合适谱线;在标准中逐级加入铁基体,考察了铁基体浓度从20μg/mL到80μg/mL时对测定Al的各谱线的干扰情况。用ICP—AES对国家标准物质GSS-1,GSS-2,GSS-3,GSS-4,GSS-5进行测定,测定值与认定值的相对误差(RE)在-0.37 %～0.31%之间,RSD(n= 5)为0.26％～0.75％ 。     

微柱分离-ICP-MS测定高纯氧化钆中14种稀土杂质

研究了采用自制微柱分离装置分离Gd2O3基体的条件。99．9％以上基体被分离，分离周期为36min。建立了高纯Gd2O3中分离Gd后测定Yb、Lu以及内标补偿法直接测定其它12种稀土杂质的ICP—MS分析方法.定量下限为0．08～0．80μg／g，加标回收率为85％～115％，相对标准偏差为1．1％～8．5％、方法可满足快速测定99．999％ Gd2O3中14种稀土杂质的要求。     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.