电感耦合等离子体原子发射光谱法分析25种元素对磷的光谱干扰及其校正

利用电感耦合等离子体原子发射光谱法分析了25种元素对磷的光谱干扰及其校正.电感耦合等离子体原子发射光谱法测定样品中磷元素含量时存在光谱干扰,通过干扰系数法,对铍、硼、镁、铝、硅、钙、钪等25种元素对磷元素的光谱干扰情况进行了分析,获得各元素的干扰系数.以国家标准物质GBW 01305为样品,利用该方法对其磷元素含量进行...     

ICP-AES法测定铜磁铁矿中铜、锰、铝、钙、镁、钛和磷量

通过样品处理、干扰试验、方法检出限、准确性和精密度试验,确定了最佳实验条件,建立了电感耦合等离子体-原子发射光谱法测定铜磁铁矿中铜、锰、铝、钙、镁、钛和磷含量的方法。试料经盐酸、硝酸、氢氟酸、高氯酸分解,用盐酸溶解盐类,过滤,采用电感耦合等离子体发射光谱法同时测定滤液中铜、锰、铝、钙、镁、钛和磷量。方法检出限：锰、钛和磷小于0.00085%,其它元素小于0.0054%,分析结果与分光光度法、XRF法和AAS法分析结果一致,8个实验室对5个水平样品进行协同试验给出了方法的精密度。     

电感耦合等离子体原子发射光谱法(ICP-AES)测定铜磁铁矿中铜、锰、铝、钙、镁、钛和磷的含量

通过样品处理、干扰实验、方法检出限、准确度和精密度实验,确定了最佳实验条件,建立了电感耦合等离子体-原子发射光谱法(ICP-AES)测定铜磁铁矿中铜、锰、铝、钙、镁、钛和磷含量的方法。试料经盐酸、硝酸、氢氟酸、高氯酸分解,用盐酸溶解盐类,过滤,采用电感耦合等离子体原子发射光谱法同时测定滤液中铜、锰、铝、钙、镁、钛和磷的含量。方法检出限为锰、钛和磷小于0.00085%,其它元素小于0.0054%,分析结果与分光光度法、X射线荧光光谱法(XRF)和原子吸收光谱法(AAS)分析结果一致,8个实验室对5个水平样品进行协同实验给出了方法的精密度。     

电感耦合等离子体原子发射光谱法测定铝锰铁中硅和磷

采用电感耦合等离子体原子发射光谱法测定铝锰铁中硅、磷的含量。选择178.242nm和251.611nm作为磷、硅的分析谱线,可消除谱线的重叠干扰。使用与分析样品基体相接近的标准样品和相同的测定条件,可克服物理干扰,并比较了酸、碱熔样方式对待测元素的影响。本法已应用于铝锰铁样品中硅、磷的测定,对照试验测定结果的相对标准偏差(n=6)不大于7.0%。     

电感耦合等离子体发射光谱法测定钢铁中的磷

探讨电感耦合等离子体发射光谱法测定钢铁中磷的方法。试验确定了微波消解器处理样品的条件、仪器最佳工作参数,研究了共存元素谱线的干扰情况。该法能够准确、快速地测定钢铁样品中0.010％～0.20％范围内的磷,测定结果的相对标准偏差RSD<5％,回收率为98％～104％。     

电感耦合等离子体原子发射光谱法测定氟铍酸铵中的杂质元素

采用电感耦合等离子体原子发射光谱法测定氟铍酸铵中的8种主要杂质元素。以超声辅助溶解样品,然后用电感耦合等离子体原子发射光谱法测定氟铍酸铵中的钠、镁、铝、铬、铁、镍、铜、磷等8种杂质元素,8种元素线性相关系数均大于0.999,测定结果的相对标准偏差为0.65%~1.55%(n=6),检出限在0.2~19.1μg/L之间,定量范围满足氟铍酸铵中8种杂质元素的限量要求。磷的加标回收率为76.7%,其余7种杂质元素的加标回收率在80.9%~95.1%之间,测量准确度满足分析要求。将电感耦合等离子体原子发射光谱法和电感耦合等离子体质谱法进行了比较,两种方法测定结果基本一致。     

端视等离子体原子发射光谱法测定无磷洗衣粉中磷

利用端视等离子体原子发射光谱法测定了无磷洗衣粉的磷标准样品,探讨了基体元素钠对磷的干扰情况,对试验条件进行了优化,检出限为0.007μg·ml-1,RSD为2.9%～3.7%。方法简便快速,结果满意。     

23种中国和法国小麦样品及小麦面粉样品中九种元素的分析

采用电感耦合等离子体发射光谱对１０种法国小麦样品,２种中国小麦样品,７种法国小麦面粉样品以及４种中国面粉样品进行了钙,镁,锌,铁,锰,铜,钼,钾及磷共９种微量和常量元素的含量分析。     

区域地球化学样品中磷、钒、铬、镍、硒等13种元素的高效测定方法研究

采用硝酸、氢氟酸、高氯酸等三种混合酸预消解,再用王水、盐酸分两次复溶提取,电感耦合等离子体质谱(IC P-M S)法测定钴、铜、钼、铅、镉,电感耦合等离子体发射光谱(IC P-O ES)法测定磷、钒、铬、锌、钾、镍、锰,原子荧光发射光谱(A FS)法测定硒,最终实现区域地球化学样品中磷、钒、铬等13种元素的准确、高效、...     

ICP—AES法测定钢铁样中硅,磷,锰,铬,镍,铜,铝

详细地研究了钢铁样中主量铁对７种被测定元素的干扰和被测定元素间的干扰情况，并研究了不同酸分解样品的效果，确定了用电感耦合等离子体发射光谱测定钢铁样中硅、磷、锰、铬、镍、铜和铝的方法。     

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.     

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.