碘化铵挥发与分离制样技术在原子荧光光谱法测定地质样品中痕量锗、锡、锑的运用

提出利用锗、锡、锑与磺化铵熔化形成挥发性碘化物的特性行为原子荧光光谱法测定地质样品中上述3种元素含量时的样品前处理和分离方法。试验表明:当将适量样品(0.5g)与碘化铵(1g)置于双球玻璃管中混匀,用喷灯直接加热至350℃以上,并保持10min后,试样中的锗、锡及锑将分别形成四碘化锗、四碘化锡及三碘化锑挥发逸出并凝聚于玻璃管壁,从而达到此3种元素与基体的分离。用盐酸将管壁上的凝聚物洗入烧杯中,再先后用硝酸蒸发除碘和用盐酸及过氧化氢溶解残渣制成溶液后即可进行原子荧光光谱测定。上述3种元素的检出限(3s/k)分别为0.08,0.06,0.08μg·L-1。     

分光光度法同时测定无机多组分体系的研究 Ⅵ 锑、锡和锗的同时测定

本文提出一个快速同时分光光度测定锑、锡和锗的方法。锑、锡和锗经磷酸三丁酯萃取后,用苯基萤光酮显色,各配合物重叠光谱的相互干扰用CPA-矩阵法处理,方法简捷,灵敏度及准确度均较好,用于合成样品及河流沉积物中锑、锡和锗的测定,获得满意的结果。     

气相色谱法测定高纯四氟化锗中的四氟化硅

高纯四氟化锗生产制备过程中,需要对四氟化锗中的四氟化硅进行测定。采用带DID氦放电离子化检测器的气相色谱仪,由一个十通阀和一个四通阀组成阀系统,使用气相色谱填充柱和超高惰性气相色谱柱分离四氟化锗中的四氟化硅,纯化后的高纯氦气作为载气和参比气。经过大量实验探究和实样测定,确定了气相色谱法测定四氟化锗中的四氟化硅的工作条件,老化时间为2h;柱箱温度为恒温55℃;载气压力为0.6MPa;参比气参比流量为30ml/min,尾吹气5ml/min;切阀时间为3.400min。经过实验验证,该方法精密度好,准确度高,四氟化锗中的四氟化硅能很好地分离,能够满足高纯四氟化锗生产中四氟化硅成分测定需求,可应用于实际测定工作中。     

低含量锡的快速比色法

应用阳离子表面活性剂的胶束增溶作用,不但提高了苯芴酮测定锡的灵敏度,而且在较大量酒石酸掩蔽下也提高了方法的选择性。在盐酸介质中能与苯芴酮、阳离子表面活性剂反应生成三元络合物的金属主要有钽、铌、锡、锗、钛、钨、钼、锑等。我们采用过氧化钠碱熔法使钽、铌、钛等沉淀而与锡分离;干扰元素钼、锑和钨可分别用过氧化氢和酒石酸隐蔽之;锗在原矿中含量甚微。因此,可不经分离直接测定锡,从而达到快速、准确、简易的目的。本法测锡不需要贵重的仪器设     

石墨炉原子吸收光谱法测定锡和锗时基体改进剂硝酸钙的作用

石墨炉原子吸收光谱法测定低温易挥发元素锡和锗时灵敏度较低。本文以硝酸钙为基体改进剂,使锡和锗的灵敏度分别比不加基体改进剂时提高9倍和50倍,同时也显著提高灰化温度,并降低原子化温度。本文也探讨了基体改进剂硝酸钙对锡和锗的增感机理。锡的增感是由于固相和气相中钙的作用,而锗的增感仅是气相钙的作用。     

气相色谱法测定罐头食品中的锡

关于食品中锡的测定方法较多,Horwitz等已有综述;Evans等用氢化物-原子吸收法测定了食品中的砷、锑、锡;Fricke等用色谱分离氢化物-等离子发射光谱法同时测定了砷、锡、锑、锗。但是,由于氢化物-原子吸收法存在着较复杂的干扰,因而在使用时受到—定限制。色谱分离氢化物-等离子发射光谱虽然可分离出共存干扰     

反相离子对高效液相色谱法分离测定钪、锡和铝

 以 1,2 二苯乙烯 4,4′ 双 (1 偶氮 ) 3,4 二羟基苯 2 ,2′ 二磺酸铵 (芪唑 )为柱前衍生试剂 ,采用反相离子对高效液相色谱法分离和测定钪、锡和铝。在C18柱上 ,用含 2 0mmol/LHAc NaAc缓冲溶液 (pH 6 0 )和 10mmol/L十二烷基磺酸钠的甲醇水溶液作流动相 ,检测波长 5 0 0nm ,同时分离测定了钪、锡和铝的络合物。钪、锡和铝的检出限分别为 0 9μg/L ,1 0 μg/L和 1 2 μg/L ,此方法用于矿石样品分析获得满意结果。     

锗的分析概况

本文是关于锗分析方法的综述，共分锗的分析和分离方法，锗的定量法和有机锗Ｇｅ－１３２产量质量控制法研究现状三大部分。锗的分析和分离方法中，介绍了锗的分析方法及分类，锗样品前处理、分离与预浓集的原理和方法，并便 出了有参考价值的图表，锗的定量法中介绍了重量法、容量法、分光光度法、荧光法和发光分析法原子吸收分光光度法、原子发射光法、电化学分析法。每一分析法中又介绍了测定法研究及应用实例。在测定法研究及应     

过渡金属重卡拜的合成、结构与反应性

过渡金属硅卡拜、锗卡拜、锡卡拜和铅卡拜是过渡金属分别与硅、锗、锡和铅之间形成三键的化合物。自从1996年首次发现钼锗卡拜以来,相继得到了一系列过渡金属锗卡拜、锡卡拜和铅卡拜化合物,而首例过渡金属硅卡拜则于2010年得以成功制备,标志着过渡金属与第14族元素之间形成三键的空白被全部填满。这些化合物的出现大大丰富和完善了过渡金属主族元素化学在成键、结构和反应方面的内容,引起化学界的重视。本文结合这方面最新的实验研究进展,系统全面总结了这些化合物的合成、结构和反应性,并对该领域的发展前景作了讨论。     

2,4-二氯苯基萤光酮-溴化十六烷基三甲基铵分光光度测定锗

2,3,7-三羚基-9取代萤光酮衍生物是测定锗的优良试剂,已有较多的报导,但钨、钼、钛、锡等干扰较为严重。我们对九种不同取代基的萤光酮测定锗的性能作了对比得出,以2,4-二氯萤光酮测锗性能最好,摩尔吸光系数达1.8×10~5,能在高达7N硫酸中显色,常起干扰的钨钼钛等元素均可存在相当大的量。系测锗选择性最好的一种试剂。一般矿石样品可不经任何分离直接测定。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.