电感耦合等离子体-质谱法测定高纯硫粉末中17种痕量杂质

建立电感耦合等离子体-质谱(ICP-MS)法测定高纯硫粉中Si、P、V、Cr、Mn、Ni、Co、Cu、As、Zn、Zr、Cd、In、Sb、Te、Pb、Bi等17种痕量金属杂质含量的方法。样品用HClO4溶解后挥发硫基体,使样品中杂质元素得到富集,各杂质元素的方法检出限为0.1～50ng/g。方法加标回收率为83%～117%。各杂质元素均为10ng/mL的混合标准溶液平行7次测定的相对标准偏差均小于5%。该方法能够满足纯度为99.999%～99.9999%的高纯硫样品中杂质测定的需要。     

激光剥蚀-电感耦合等离子体质谱对高温合金中17种痕量元素的测定

建立了镍基高温合金中Sc、Cu、Zn、Ga、Ge、As、Ag、Cd、In、Sn、Sb、Te、Ce、Hf、Tl、Pb、Bi17种痕量元素的激光剥蚀-电感耦合等离子体质谱测定方法。对激光剥蚀进样及质谱分析条件进行了优化,通过激光对样品表面的层层剥蚀顺利完成了对低沸点杂质元素的测定。采用格栅扫描采样,严格控制样品的聚焦位置和散焦距离以保证采样的准确性,由高温合金系列标准物质建立了18种痕量元素的校正曲线,其中14种痕量元素的线性相关性较好(r2≥0.99),In、Sn、Sb、Ce、Tl、Pb、Bi等超痕量元素的检出限和气体空白分别低于或接近0.000 005%和0.000 001%。方法对镍基高温合金样品中Cu、Ga、Ag、Cd、In、Sn、Sb、Te、Hf、Tl、Pb和Bi等痕量元素的测定结果与参考值吻合较好,且大部分元素的RSD(n=4)小于或接近30%。     

电感耦合等离子体质谱法测定多西他赛注射液中17种元素

建立电感耦合等离子体质谱（ICP-MS）法测定多西他赛注射液中17种元素（Al、As、Ba、Cd、Co、Cr、Cu、Fe、Hg、Li、Mn、Ni、Pb、Sb、Tl、V、Zn）。采用浓硝酸与过氧化氢作为消解液，经微波消解处理样品后，用ICP-MS法进行测定。Hg质量浓度在0.05～4 ng/mL范围内、其余16种元素质量浓度在0.5～40 ng/mL范围内线性关系良好，相关系数均大于0.999，各元素的检出限为0.000 5～0.6 mg/kg，样品加标回收率为92.2%～108.8%，测定结果的相对标准偏差为1.1%～2.8%。该方法操作简便，线性范围宽，分析速度快，灵敏度高，可同时测定多种元素，适用于多西他赛注射液中多种元素的测定。     

前列舒通胶囊中26种无机元素的分析

目的：明确造成前列舒通胶囊不同批次间差异的标志性无机元素,并进行安全性评价。方法：采用ICP-MS测定制剂中Al、As、B、Ba、Ca、Cd、Co、Cr、Cu、Fe、K、Mg、Mn、Mo、Na、Ni、Pb、Sb、Se、Sn、Sr、Ti、Tl、V、Zn和Hg元素含量并进行数据分析。运用主成分及综合评分结合聚类分析手段,确定制剂的特征性元素;进行元素含量和相关性分析,明确不同批次各元素的差异及元素之间的关系;以多元素含量为指标,绘制无机元素谱图。结果：19批样品中均未检测出Se、Mo、Sn、Sb、Tl和Hg,且Pb、Cd、As、Cu、Hg均符合限量标准,无机元素含量谱图趋势一致。主成分分析提取了4个主成分,确定元素B、K、Al、V、Cr、Ca、Ti、Na、Co和Mn可作为特征元素。主成分得分图将19批样品分为两类,聚类分析及综合评分结果与其一致,两类样品中各元素含量存在差异性。相关性分析中,明确了B与K、Al、Cr正相关,K与Cr、Co正相关,V与Cr、Mn正相关,Mn与Co正相关,Ca、Ti、Na两两正相关。结论：通过分析前列舒通胶囊中无机元素含量,确定了特征元素,为前列舒通胶囊质量全面控制研究提供科学依据。     

微波消解ICP-MS快速测定生物样品中的多种元素

建立了微波辅助HNO3消解样品,ICP-MS快速测定生物样品中Ti、Cr、Mn、Fe、Co、Ni、Cu、Zn、Ge、As、Se、Sr、Mo、Ag、Cd、I、Ba、Hg、Tl、Pb、Bi共21种微量及痕量元素。通过在线加入内标来校正基体效应和信号漂移对测量所造成的影响。各元素线性相关系数在0.9990以上,RSD小于6.0%。用本方法对国家标准样品GBW07601a(头发),GBW10010(大米),GBW10016(茶叶),GBW10023(紫菜)进行分析,结果满意。方法能满足生物样品痕量分析的要求。     

高纯钛的辉光放电质谱法多元素分析

采用辉光放电质谱法(GD-MS)测定高纯钛中Mg、Al、Cr、Fe、V、Mn、Co、Ni、Cu、Zn、As、Sn、Sb、Ta、W、Pb、Bi等痕量杂质元素,并对GD-MS工作参数及条件进行了优化。主要元素与内标校正ICP-MS法定量分析的结果一致,对结果差异的原因进行分析,论述了Element GD辉光放电质谱仪在痕量杂质元素分析方面的优势。     

电感耦合等离子体质谱法同时测定植物类新食品原料中14种无机元素北大核心CSCD

0.500 0g样品经硝酸3mL、过氧化氢2mL消解后,采用电感耦合等离子体质谱法同时测定样品溶液中Na、Mg、Ca、Al、Cu、Zn、Fe、Mn、Se、Pb、Cd、As、Hg和Cr的含量。采用0.5%(体积分数)硝酸的基体酸度增强分析元素的信号强度;在两次测试之间用100μg·L-1 Au-5%(体积分数)硝酸溶液清洗仪器,降低Hg的吸附效应;利用甲烷碰撞动态反应池技术消除了分析过程中的质谱干扰,选择Sc、Y、In、Bi为内标元素校正基体效应。14种元素的质量浓度在一定范围内与信号强度呈线性关系,检出限(3s)在0.003~0.039μg·L^(-1)之间。方法用于分析国家标准物质GBW 10027,各元素测定值与认定值相符,测定值的相对标准偏差(n=6)在1.6%~14%之间。     

微波辅助消解-电感耦合等离子体原子发射光谱法(ICP-AES)测定几种血藤中17种元素

建立电感耦合等离子体原子发射光谱法(ICP-AES)测定血藤类中药中K,Ca,Mg,P,Sr,Fe,Mn,Zn,Cu,Co,Cr,Al,Ba,Ni,As,Pb和Cd 17种常量和微量元素含量的分析方法。样品用微波辅助消解,ICP-AES法检测几种血藤中17种元素的含量,方法的检出限为0.000 03~0.009 81μg/mL,加标回收率88.37%~110.00%,相对标准偏差(RSD)均小于5.0%,方法可快速、灵敏、准确测定血藤类中药中多种常量、微量元素的含量。血藤样品中除含有人体必需的常量元素K,Ca,Mg外,还含有Fe,Zn,Mn,Cr,Co等必需的微量元素和其它元素P,Ni,Ba,Al,Sr,Pb,Cd,Ba等。     

电感耦合等离子体质谱法同时测定植物类新食品原料中14种无机元素

0.500 0g样品经硝酸3mL、过氧化氢2mL消解后,采用电感耦合等离子体质谱法同时测定样品溶液中Na、Mg、Ca、Al、Cu、Zn、Fe、Mn、Se、Pb、Cd、As、Hg和Cr的含量。采用0.5%(体积分数)硝酸的基体酸度增强分析元素的信号强度;在两次测试之间用100μg·L-1 Au-5%(体积分数)硝酸溶液清洗仪器,降低Hg的吸附效应;利用甲烷碰撞动态反应池技术消除了分析过程中的质谱干扰,选择Sc、Y、In、Bi为内标元素校正基体效应。14种元素的质量浓度在一定范围内与信号强度呈线性关系,检出限(3s)在0.003~0.039μg·L~(-1)之间。方法用于分析国家标准物质GBW 10027,各元素测定值与认定值相符,测定值的相对标准偏差(n=6)在1.6%~14%之间。     

微波辅助消解ICP-AES法测定几种血藤中17种元素*

目的 建立电感耦合等离子体发射光谱(ICP-AES)法测定血藤类中药中K、Ca、Mg、P、Sr、Fe、Mn、Zn、Cu 、Co、Cr、Al 、Ba、Ni、As、Pb和Cd17种常量和微量元素含量的测定方法。方法 采用微波辅助消解样品,电感耦合等离子体发射光谱(ICP-AES)法测定几种血藤中17种元素的含量。 结果 该方法的检出限为0.00003~0.00981μg/mL,回收率88.37% ~110. 00%,相对标准偏差( RSD) 均小于5.0%。结论 该方法可快速、灵敏、准确测定血藤类中药中多种常量、微量元素的含量。血藤样品中除含有人体必需的常量元素K、Ca、Mg外,还含有Fe、Zn、Mn、Cr、Co等必需的微量元素和其它元素P、Ni、Ba、Al、Sr、Pb、Cd、Ba等。     

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.     

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.     

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.     

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.     

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.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.