氢化物原子荧光法测定中草药中痕量铅

提出了以重铬酸钾为氧化剂、碱性铁氰化钾为络合剂 ,在柠檬酸介质中进行铅的氢化物发生反应。采用断续流动氢化物发生器 ,对原子荧光法测定痕量铅的条件进行了系统研究 ,并考察了共存元素的干扰情况。在最佳测试条件下 ,测得铅的检出限 (3σ)为 0 .19μg·L- 1,相对标准偏差为 0 .92 %。应用于中草药中痕量铅的测定 ,回收率为 95 .1%～ 10 9.5 % ,结果满意     

微波消解-氢化物发生原子荧光法测定塑料原料及其制品中的砷、汞

采用微波消解进行样品前处理，以硫脲为预还原剂，用氢化物发生原子荧光法测定塑料原料及其制品中的砷、汞。测定砷和汞的线性范围均为0～8μg／L，砷、汞的检出限分别为0．005、0．076μg／L，测定结果的相对标准偏差分别为4.96％～7．38％、2．94％～7．20％(n=6)，回收率分别为92．0％～103．2％、92．0％～98.0％。     

Two noncentrosymmetric complexes: [W(CO)4(bipy)] and [W(CO)4(phen)](bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline) obtained through solvothermal synthesis and their optical properties

Solvothermal treatments of W(CO)₆ with 2,2′-bipyridine and 1,10-phenanthroline give [W(CO)₄(bipy)] (1) and [W(CO)₄(phen)] (2), respectively, which both crystallize in noncentrosymmetric space groups, suggesting that they meet the requirement of second harmonic generation (SHG) investigations. The preliminary experiment indicates that they are SHG active, and approximately estimated to be that of urea.     

流动注射在线共沉淀HG-AFS测定痕量铅

建立了流动注射在线共沉淀HG-AFS测定痕量铅的分析方法。方法基于铅在碱性介质中与氢氧化镁共沉淀，沉淀收集在锥形沉淀腔中，用HCl溶洗沉淀和NaBH4反应，产生的氢化物被载气引入原子化器中进行测定。测定铅的RSD为3％(5ng/mL，n=10)，检出限为0．01ng。检出限较直接进样降低了11倍。对国家标准物质中铅的测定结果与标准值相符。     

二乙基二硫代氨甲酸银体系流动注射法测定砷

本文设计了一种ＡｇＤＤＣ流动注射－分光光度法测定砷的系统。该系统采用自制的氢化物发生及吸装置，将液体流路和载气流路结合在一起。     

Electronic spectrum of dibiphenylene-ethene radical anion

The electronic absorption spectrum for the dibiphenylene-ethene radical anion ( ), generated electrochemically in dimethylsulfoxide solutions, is reported. Based on calculations by the LCAO-MO method in theHückel approximation and on the analysis of the band positions it is suggested that in the molecule two planar fluorenylidene fragments are twisted (60°) about the central C=C bond.

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Das Elektronenabsorptionsspektrum des Dibiphenylen-Radikalanions (Kurze Mitteilung)

Zusammenfassung Das Dibiphenylenethen-Radikalanion ( ) wurde elektrochemisch hergestellt und das Elektronenabsorptionsspektrum aufgenommen. Auf Grund von LCAO-MO Berechnungen in derHückel-Annäherung und der Analyse der Bandenlagen wird nahegelegt, daß im -Molekül zwei planare Fluorenyliden-Fragmente ca. 60° um die zentrale C=C-Bindung verdrillt angeordnet sind.

     

流动注射氢化物石墨炉原子吸收法的应用研究 Ⅰ.——实验装置与分析性能

氢化物石墨炉联用技术的原理是先在较低温度下将氢化物蒸气通入石墨炉并分解沉积于石墨管的内表面,然后再在高温下原子化。该法能明显提高灵敏度,消除液相和气相干扰。本文采用自制的半自动氢化物石墨炉进样系统及流动注射氢化物发生器,直接在普通石墨炉上进行氢化物石墨炉分析,研究了部分元素的测定条件,建立的方法操作方便,灵敏度高,耗样少,线性范围宽,是一种值得推广的新方法。     

氢化物发生石墨炉原位富集直接测定高温镍基合金中碲

通过选择碲的氢化物发生条件，克服了高含量镍对碲的干扰，把氢化物富集在涂钯石墨管里，然后再原子化，成功地测定了高温镍基合金中碲。     

丹宁纤维素富集-氢化物发生ICP-AES同时测定水中痕量锗

研究了丹宁纤维素富集10~(-11)g/ml级锗的条件,并考察了地下水中36种共存离子对磷酸介质中氢化物发生ICP-AES测定锗的干扰和消除,应用于测定地下水中的超痕量锗,结果满意,检出限为15ng/L。     

Computer generation of chemical structures from known fragments

The interactive generation of chemical structures from given fragments is described and discussed. It is implemented as a part of our expert system CARBON, based on C-13 NMR spectra. As it is designed, this program can also be a useful tool in the structure elucidation process when information on parts of the structure is obtained by other means (IR, mass and other spectrometries, chemical analysis, other relevant information). The topological characteristics of candidate fragments are first chosen interactively and then the elements are connected in all topologically possible ways. In the following step, the topological building blocks are substituted by chemical structural fragments resulting in a set of all chemical structures consistent with the input information.