共查询到20条相似文献,搜索用时 62 毫秒
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联用技术测定富硒农产品中硒的形态研究进展 总被引:1,自引:0,他引:1
硒的营养功能与农产品硒的形态息息相关。联用技术作为元素形态分析的有效方法,近年来受到了人们广泛关注。对用联用技术测定富硒农产品中硒的形态研究现状及进展进行了综述,包括前处理技术、色谱分离技术和定量检测方法等3个方面。 相似文献
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沉积物样品中痕量元素汞的形态分析研究进展 总被引:1,自引:0,他引:1
归纳总结了沉积物中汞形态分析研究进展,内容包括沉积物汞的赋存形态,样品的预处理和不同形态汞的原子光谱法、色谱法、电感耦合等离子体质谱法及联用技术等分析方法,指出了存在的问题和未来的发展方向。 相似文献
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电感耦合等离子体质谱(ICP-MS)联用技术的应用及展望 总被引:2,自引:0,他引:2
总结了ICP-MS联用技术在国内外检测领域的最新应用,并就"分离器与ICP-MS"、"进样系统与ICP-MS"、"ICP-MS与其它仪器物理联用"等联用技术进行了分类、拓展和总结。ICP-MS联用技术的发展重点将倾向于提高分析精密度、复杂基体元素超痕量分析、同位素比值及形态研究领域,相关联用技术的国家标准或行业标准出台已迫在眉睫。 相似文献
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二恶英类分析研究进展及展望 总被引:2,自引:0,他引:2
通过综合介绍国内外二恶英类物质分析研究的最新动态,包括二恶英类的前处理和气相色谱法(GC)、液相色谱法(LC)、胶束电动色谱法(MEKC)、质谱法(MS)、气相色谱/质谱(GC/MS)联用和生物分析法等多种分析技术及其改进方法,指出了二恶英类分析研究工作中现存的问题,对今后的发展动向提出了一些建议。 相似文献
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二英类分析研究进展及展望 总被引:4,自引:0,他引:4
通过综合介绍国内外二英类物质分析研究的最新动态,包括二英类的前处理和气相色谱法(GC)、液相色谱法(LC)、胶束电动色谱法(MEKC)、质谱法(MS)、气相色谱/质谱(GC/MS)联用和生物分析法等多种分析技术及其改进方法,指出了二英类分析研究工作中现存的问题,对今后的发展动向提出了一些建议. 相似文献
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固相微萃取技术在形态分析中的应用进展 总被引:3,自引:0,他引:3
形态分析比传统的元素分析能提供更为丰富的信息,成为当今分析化学领域前沿课题之一,而固相微萃取(SPME)是近十年来发展起来的新型分离富集技术,简便快速、无污染、易于和其它技术联用.近几年来才开始将固相微萃取应用到形态分析,二者结合对形态分析的发展具有促进作用,本文就固相微萃取技术在元素有机化合物形态分析中的应用进行了评述. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
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. 相似文献
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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. 相似文献
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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%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
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. 相似文献
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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. 相似文献
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An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions. 相似文献
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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. 相似文献
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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. 相似文献
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An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction. 相似文献
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The Diels-Alder reactivity of 1,2-heteroborines (H4C4B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed. 相似文献