ChemInform Abstract: Metastable Isonitrosyl Structure of the Nitroprusside Anion Confirmed by Nuclear Inelastic Scattering.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

N催化剂中活性组分的核磁共振氢谱定量研究

建立了测定无对照品的N催化剂中活性组分含量的核磁共振氢谱内标测定法。以氘代甲醇为溶剂,对苯二酚为内标物,设定合适的采样时间和延迟时间,选取适合的内标峰和样品定量峰。采用优化后的实验参数进行定量分析,经计算得其中的活性组分磷酸三丁酯(TBP)、邻苯二甲酸酐开环产物(PA-DCPTi Cl3)、环氧氯丙烷开环产物(DCP-Ti Cl3)和邻苯二甲酸正丁酯(DNBP)的质量分数分别为0.21%、0.58%、1.21%和5.82%,相对标准偏差(RSD)分别为0.75%、0.89%、0.41%和0.35%,其结果的重复性和可靠性良好,与高效液相色谱法测定结果一致。该方法具有无需标准对照品、快速、高效等特点,在利用核磁共振技术研究N催化剂中活性组分的化学结构时可同时测定其含量,为催化剂中给电子体含量的表征建立了新途径。     

ChemInform Abstract: Characterization of the Oxo-Anions of Bromine BrO- x (x = 1-4) by IR,NMR, and Bromine K-Edge Extended X-Ray Absorption Fine Structure Techniques.

This detailed spectroscopic and structural study of the complete series BrO- x (x = 1-4) for the first time yields a value for the bond length in the hypobromite ion.     

核磁共振定量法测定利培酮含量

采用氢核磁共振定量法和氟核磁共振定量法测定利培酮含量。氢核磁共振定量法以利培酮δ7.29~7.35处质子峰为定量峰,马来酸δ6.02处为内标峰,在恒温300 K,采样时间4.0 s,弛豫延迟时间15 s,扫描次数为32次条件下采集氢谱。氟核磁共振定量法以4-溴-2-氟-乙酰苯胺为内标,在恒温300 K,谱宽12 500.0 Hz,中心频率-43 662.7 Hz下采集氟谱。测试结果显示,利培酮氢核磁共振定量法和氟核磁共振定量法的含量测定结果基本与质量平衡法的结果一致。因此,核磁共振法可用于利培酮绝对含量的测定,具有快速、简单、准确的优势。     

定量核磁共振波谱法同时测定中药虎杖中白藜芦醇和虎杖苷的含量

建立了定量核磁共振波谱法同时测定虎杖中白藜芦醇和虎杖苷的方法。样品用80%乙醇和丙酮两次超声提取净化,再用定量核磁共振波谱法测定。考察了样品预处理和核磁共振实验条件对测定结果的影响,选择氘代二甲亚砜-重水(10∶1,V/V)为溶剂,用基准物质邻苯二甲酸氢钾标定的2,3,5-三碘苯甲酸为内标,选择脉冲延迟时间为5 s,采样次数为32次。定量峰为6.388~6.391(白藜芦醇:H-2,6,d,2H)和6.322~6.330(虎杖苷:H-4,t,1H)。结果表明,NMR测定的精密度均小于0.6%,线性相关系数(r)均大于0.999,白藜芦醇和虎杖苷的检出限分别为0.23和0.24 g/L,定量限分别为0.69和1.57 g/L,包括样品提取过程的回收率分别为97.7%~103.5%(RSD=2.4%)和94.5%~99.2%(RSD=1.6%),显示出定量核磁共振法在中药定量时的可靠性。实际测定4种虎杖饮片及配方颗粒样品中白藜芦醇和虎杖苷含量分别为3.57~5.69 mg/g和12.73~24.07 mg/g。     

ChemInform Abstract: Multinuclear Magnetic Resonance Studies of the Hydrolysis of Aluminum(III). Part 8. Base Hydrolysis Monitored at Very High Magnetic Field.

Using high-field ¹H and ²⁷Al NMR spectroscopy with increased sensitivity data can be obtained at concentrations as low as 1·10^-3 mol/dm³.     

ChemInform Abstract: Characterization of the GaO4Al12(OH)24(H2O)7+ 12 Polyoxocation by MAS NMR and IR Spectroscopies and Powder X-Ray Diffraction.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: NMR of 129Xe Trapped in Clathrates and Some Other Solids.

129Xe NMR chemical shifts, obtained for Xe trapped in the cages of clathrate hydrates and a clathrasil sample, together with shift data for solid Xe correlate linearly with the mean free radius of the cage.     

固相萃取/定量核磁共振波谱法测定乳增宁胶囊中的淫羊藿苷

建立了固相萃取(SPE)/定量核磁共振波谱(q NMR)无标样测定乳增宁胶囊中有效成分淫羊藿苷含量的方法。样品用10%乙醇室温下超声提取,以HC-C18型SPE柱对提取液进行浓缩除杂后,用q NMR测定淫羊藿苷的含量。考察了超声时间、SPE样品前处理条件以及定量核磁共振实验条件对定量结果的影响。选择氘代二甲基亚砜为溶剂,2,3,5-三碘苯甲酸为内标,并用基准试剂邻苯二甲酸氢钾对其进行标定。选择脉冲宽度P1=14.1μs,扫描次数NS=256为q NMR定量淫羊藿苷的实验条件。淫羊藿苷的定量峰为δ7.9(2',6'-H,d,2H)。结果显示,所建方法的日内精密度RSD为0.43%,日间精密度RSD为0.75%,淫羊藿苷与2,3,5-三碘苯甲酸峰面积比与质量比的零截距标准曲线的线性相关系数为0.999 9,且斜率与理论值相符。该法测定淫羊藿苷的LOD为0.122 mg/g;LOQ为0.368 mg/g。样品经SPE预处理后淫羊藿苷的回收率为99.8%~103.0%。可在不用对照品的情况下对乳增宁胶囊中淫羊藿苷的含量进行测定。