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。     

电感耦合等离子质谱法测定化妆品中的有害元素

用电感耦合等离子质谱法测定了抽检化妆品中有害元素Pb、As、Hg.采用内标元素Sc校正As,内标元素Eu校正Pb和Hg,获得满意的测定结果.方法检出限为0.03～0.05 ng/mL,变异系数（CV%）为0.3%～5.0%,加标回收回收率为95%～105%.     

浸提法-ICP-AES测定化妆品中有害元素铅、砷、汞

建立了浸提法-电感耦合等离子体发射光谱(ICP-AES)测定化妆品中Pb、As、Hg的方法,并对ICP-AES工作参数及条件进行了优化和选择.Pb、As、Hg检出限分别为0.0078,0.011和0.023 μg/mL.线性范围为0～500 μg/L,相对标准偏差为1.3%～3.9%;回收率为90%～101%.适用于化妆品中Pb、As、Hg的日常检测.     

微波消解-石墨炉原子吸收光谱法快速测定食品中铁、钠、铜、铅、砷和镉

应用微波消解溶样,石墨炉原子吸收光谱法测定食品中的Fe、Na、Cu、Pb、As和Cd等多种元素.Fe、Cu、Na、Pb、As和Cd分别在0.01～0.08,0.1～2μg/mL,5～40,0.5～4,5～25,1～5μg/L范围内有良好的线性关系,其线性相关系数均在0.9998以上.用该方法测定标准物质GBW(E)080684大米粉,结果相对误差均在允许范围内.     

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。     

三种消解方法在测定近海沉积物中Pb、 Cu、 Cd、 Hg及As的应用

常压湿式消解、高压微波消解、常压微波消解3种方法被应用于近海沉积物中Pb、 Cu、 Cd、 Hg、 As 5种重金属元素的分析. 以近海海洋沉积物标准物质为样品经3种方法消解后, 通过石墨炉原子吸收法测定Pb、 Cu、 Cd和氢化物发生原子荧光法同时测定Hg、 As. 结果表明, 样品经常压湿式消解, 其Pb、 Cu、 Cd回收率在80%～123%内而Hg、 As回收率低;经高压微波消解, 标样中Pb、 Cu、 Cd、 As回收率在84%～117%内, 对Hg测定回收率偏低;常压微波消解更适合于Cu、 Cd、 Hg、 As的消解, 其回收率在95%～121%之间而Pb回收率低于42.4%. 常压湿式消解与常压微波消解被用于大亚湾人工渔礁区沉积物样品的处理, 有较好的测定结果.     

化学蒸气发生-四通道原子荧光光谱法同时测定水样中的痕量砷、锑、硒和汞

应用自行设计的化学蒸气发生-四通道无色散原子荧光光谱仪,建立了同时测定水样中As、Sb、Se、Hg的新方法.在实验中优化了四元素同时化学蒸气发生条件和测定的最佳工作参数.在样品预处理阶段用HCl将Se6+还原为Se4+,然后用质量浓度5 g/L硫脲将As5+和Sb5+还原为As3+和Sb3+.在最佳条件下,方法对As、Sb、Se、Hg的检出限分别为0.05、0.03、0.05、0.01 ng/mL(3d);RSD分别为0.42%、0.74%、0.97%、1.0%(对5 ng/mL As、Sb、Se和0.5ng/mL Hg混合标准,n=7).用所建立的方法对不同类型水样中的As、Sb、Se、Hg进行了同时测定,测定结果与用标准方法测定所得结果之间无明显差异,各元素的加标回收率在93%～105%.     

微波消解-电感耦合等离子体质谱法测定人面果树中的重金属元素

建立了微波消解-电感耦合等离子体质谱(ICP-MS)法测定人面果树中As,Cr,Cd,Pb,Ni,Se,Hg 7种重金属元素含量的方法。样品采用HNO3-H2O2消解体系,避免了赶酸的操作,经微波消解后,用电感耦合等离子体质谱(ICP-MS)测定样品中As,Cr,Cd,Pb,Ni,Se,Hg 7种重金属元素的含量。方法对7种元素的校准曲线的相关系数r>0.9997,检出限在0.0098～0.0874μg/L之间,回收率在93%～115%之间,RSD在0.41%～4.9%。     

微波消解-端视ICP-AES测定茶叶中微量重金属元素

采用微波消解-端视等离子体原子发射光谱(ICP-AES)测定茶叶中微量重金属元素Pb、As、Cd、Cu、Fe,并对ICP-AES工作参数及条件进行了优化和选择。Pb、As、Cd、Cu、Fe的检出限分别为2.9×10-3μg/mL、5.2×10-3μg/mL、0.056×10-3μg/mL、0.55×10-3μg/mL、0.59×10-3μg/mL,线性范围为0~10000μg/L,相对标准偏差为1.7%~8.5%;回收率为90%~104%。该方法与国标法比较,结果无显著性差异。本法能用于茶叶测定。     

高精度X射线荧光光谱法快速分析人体血液中6种有毒重金属元素

通过高精度X射线荧光光谱法建立了人体血液中As, Sr, Cd, Hg, Tl, Pb 6种有毒重金属元素的快速定量检测方法。根据每种元素的校准曲线，使用基本参数法对基体效应进行校正，建立了人体血液中有毒重金属的检测模式。6种元素在各自线性范围内呈良好的线性关系，相关系数均大于0.995，检出限在0.037～0.192 mg/L之间，加标回收率为90.1%～114.0%，相对标准偏差（RSD）在0.1%～11%之间。该方法不需前处理即可实现对人体血液中As, Sr, Cd, Hg, Tl, Pb 6种有毒重金属元素的快速测定。     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

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.     

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.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

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.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

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.