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高纯金属镱中杂质元素的电感耦合等离子体质谱法测定 总被引:5,自引:1,他引:4
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。 相似文献
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感耦等离子体质谱法测定高纯氧化镥中14个痕量稀土杂质 总被引:3,自引:1,他引:3
本文报道了用感耦等离子体质谱法(ICP-MS)测定高纯氧化镥中14个稀土杂质的方法。镥基体对测定元素无谱线干扰,但对测定信号产生显著抑制作用。加入内标后有效地补偿了这种基体抑制效应,方法检出限为0.005~0.03ng/mL。样品加标为0.01μg时,回收率为90%~103%。精密度(RSD)为1.4%~4.2%。方法简单,不需分离富集,样品消耗量少(10mg)。14个稀土元素的总测定下限(10)可达0.58μg/g可直接测定纯度为99.9%~99.9999%的氧化镥中稀土杂质。 相似文献
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三重串联电感耦合等离子体质谱法直接测定高纯氧化钕中14种稀土杂质元素 总被引:1,自引:0,他引:1
建立了三重串联电感耦合等离子体质谱(ICP-MS/MS)法直接测定高纯钕中的14种稀土杂质元素的方法.采用氧气和氨气反应池在串联质谱MS/MS模式,有效克服了基体对待测元素的干扰.通过优化仪器参数得到Tb,Dy和Ho的背景等效浓度分别为22,40和4 ng/L.在选定的条件下,样品加标0.5 μg/L14种混合稀土标样测得的回收率为88.6% ~ 98.6%,使用仪器标准配置的耐高盐进样系统(HMI)测得2h信号值的相对标准偏差(RSD)为1.3%-4.1%.本方法简单实用,能够满足纯度为5N (99.999%)及以上的高纯钕中14种杂质元素的直接测定. 相似文献
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ICP-MS 法测定高纯氧化铕中稀土杂质的研究 总被引:5,自引:1,他引:4
深入考察了ICP-MS法测定高纯氧化铕时基体对稀土杂质测定的影响,研究了P507萃淋树脂分离大量基体Eu2O3的实验条件,建立了采用内标补偿直接测定大部分稀土杂质和经P507萃淋树脂分离基体后测定被干扰离子Tm相结合的高纯Eu2O3中稀土杂质的ICP-MS分析方法。方法检出限为0.005~0.021μg/L,加标回收率为84%~112%。RSD为1.4%~8.1%。本法适用于质量分数为99.99%~99.9999%的高纯Eu2O3中稀土杂质的分析。 相似文献
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ICPMS测定高纯氧化钇中痕量稀土杂质的研究 总被引:14,自引:0,他引:14
研究了直接电感耦合等离子质谱(ICPMS)测定99.999%纯度氧化钇中稀土杂质的方法,详细探讨了仪器工作参数对稀土元素的测定的影响,对各种干扰现象进行了研究,并提出定量校正方法,实验表明,加入内标元素可有效地克服基体效应、接口效应和仪器工作参数漂移的影响。方法的检出限为0.003~0.02ng/ml,变异系数(CV%)为0.2%~5.4%,回收率为90%~115%。适合99.0%~99.999% 相似文献
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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%。 相似文献
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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%. 相似文献
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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. 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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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. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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. 相似文献
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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. 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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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. 相似文献