计算机处理三组分重叠峰法在高效液相色谱法中的应用——钐、钆、镝的同时测定

本文以二甲酚橙为显色剂、甲醇-水(含CTMAB和缓冲溶液)为流动相,利用可编辑的时间程序求得某一保留时间和波长处的电频值对Sm、Gd、Dy混合组分体系进行了考察,提出了一种处理三组分重叠峰法的计算机程序。试验结果表明,该程序简单、快速,计算结果准确度较高。     

拓扑指数法研究稀土显色剂结构与钇显色反应灵敏度的关系

本文计算了二十种不对称色酸双偶氮膦酸型显色剂的Am指数, 并将其与钇进行显色反应的灵敏度进行相关性研究, 讨论了显色剂结构对显色反应灵敏度的影响,预报了几种显色剂与钇显色反应的灵敏度, 取得较为满意的结果。     

拓扑指数法研究稀土显色剂结构与铈显色反应对比度的关系

计算了４３种不对称变色酸双偶氮膦酸型显色剂的Ａｍ拓扑指数，并将其与结构选择性因子相结合，用于偶氮类显色剂结构与铈显色反应对比度的相关性研究，讨论了显色剂结构对拓扑指数有译比度的影响。     

比色法测碘酸铜溶度积常数实验的改进

现行教材中以氨水做显色剂,比色法测定碘酸铜溶度积常数,有一定的环境污染。本实验以甘氨酸替代氨水作为显色剂,通过紫外-可见吸收光谱考察甘氨酸与铜离子反应的时间以及甘氨酸的最佳用量,从而获得配制甘氨酸合铜(Ⅱ)溶液的最佳条件,进而测定该条件下配制的各溶液的吸光度,最终获得碘酸铜饱和溶液中铜离子的浓度并计算得到与文献值接近的溶度积常数。该实验可避免实验过程中挥发性腐蚀性气体的释放,且溶液可浓缩回收甘氨酸合铜(Ⅱ),避免了环境污染,是一种绿色实验方法,在人数众多的基础实验教学中具有适用性。     

用蒙特卡罗程序对HPGeγ谱仪做能谱模拟和探测效率计算

利用蒙特卡罗方法的MCNP程序对HPGeγ谱仪探测系统建模,做能谱模拟和放射性标准土壤的探测效率计算,并与实验测量能谱相比较。由此得出结论,用MCNP程序不仅可以获得与实验相同特征的γ能谱,而且对探测效率的计算结果与实验结果符合程度较为理想。     

大学实验教学中数据处理系统的开发和应用*

借助专业软件开发数据处理系统逐渐取代了传统的人工计算过程。以“化学海洋学实验”课程的数据自动处理为研究案例,介绍了数据处理系统的开发和应用过程。该系统的计算程序用R语言编写,用Java语言实现可视化,可以用实验数据快速得到最终结果并监测实验中间环节,简化了计算程序。教师可以及时检查学生实验数据的可靠性和准确性,有效地提高了教学效率。     

双波长分光光度法测定微量镁及其在高纯氧化钇中的应用

我们对以二甲苯胺蓝Ⅱ为镁的显色剂,用双波长分光光度测定镁的方法进行探索。实验表明,本方法的灵敏度比通常的分光光度法约高三倍,消除了显色剂背景的影响,成功地实现了显色剂的吸收曲线与络合物的吸收曲线相互重叠时的测定,使标准曲线斜率增高而且线性关系更为良好,为微量镁的测定提供了一个高灵敏度的方法,初步用于高纯氧化钇中镁的测定,结果与原子吸收法一致。 (一)实验部分 1.主要仪器和试剂: (1)双波长分光光度计:自行组装。 (2)pH10硼砂缓冲液:25克硼砂溶解于1000毫升热水中,加5.7克氢氧化钠,     

程序涂渍柱“柱效能程序效应”的研究

本文从理论上给出程序柱“柱效能程序效应”的概念并导出了函数关系式,通过计算机可计算柱效能程序效应与柱内各变量之间的关系,实践证明实验数据的变化趋势与理论数据相符。     

一组不对称变色酸双偶氮肿类试剂的合成及其与稀土等元素显色反应研究

本文设计、合成了一组新的不对称变色酸双偶氮胂类稀土显色剂。对新试剂进行了提纯鉴定,确定了组成及结构,研究了它们与稀土、钍、锆的显色反应性能。实验证明,试剂分子结构对其反应性能的影响有一定的规律性。其中o-As-DBN试剂是较优良的钍显色剂,毫克级的稀土、铀不干扰测定。     

考马斯亮蓝显色剂变色反应机理的研究

应用光谱法研究了考马斯亮蓝G-250（CBBG）显色剂变色反应的机理，考察了 不同实验条件对CBBG显色剂吸收光谱的影响。研究结果表明，CBBG显色剂在反应体 系中呈现出从蓝色→绿色→棕红色等多种颜色变化，主要是由CBBG分子间疏水相互 作用形成的聚集体聚集程度的不同所引起的。     

有机光度显色剂性能的PPP法研究(Ⅱ)

光度分析的主要方向是研制对金属离子具有高灵敏度与高选择性的有机光度显色剂。通常作法是对给定分析功能团的母体,根据经验引入不同位置与类型的取代基,或通过寻找新的分析功能团,以期得到分析性能上的改善。     

Effect of surfactants on the fluorescence intensity of organic reagents

The effect of 45 surfactants on the fluorescence intensity of 12 organic reagents has been studied and discussed. It has been found that there is a marked enhancement in the fluorescence intensity of organic reagents with nonrigid structures and with phenyl groups closely located.     

Studies towards understanding the mechanism of organic reagent enhancement in flame and plasma atomic absorption spectrometry

A series of organic reagents have been tested in atomic absorption measurement for signal enhancement of metal elements. Organic reagents like tetrabutylammonium bromide are demonstrated to enhance the absorption sensitivity to some specific elements such as calcium and chromium. A group of amines were found to have significant enhancement for chromium and calcium measurements. The function of organic reagents in flame and plasma atomic absorption spectrometry (AAS) was investigated in this work with emphases on mechanism of signal enhancement and interference suppression. An alternative mechanism of organic reagent enhancement in flame and plasma AAS has been suggested based on the experimental results obtained in this work. The reduction environments in flame and plasma produced by the organic reagents are considered as major reason for the signal enhancement.     

Benzil and Benzoin: General Spray Reagents for the Visualization of Organic Compounds on Thin Layer Chromatograms

Benzil and Benzoin spray reagents have been adopted to detect some organic compounds on thin layer chromatograms (TLC). These reagents were found to visualize sugars, amino acids, dicarboxylic acids and some natural products on thin layer plates. Colors produced with these reagents were shades of the spectrum and characteristic of individual or class of the organic and natural products.     

Versatile Use of Carbon Dioxide in the Synthesis of Carbamates

Summary. Organic carbamates classically have been synthesized using harmful and toxic reagents like phosgene, its derivatives, and carbon monoxide. Recently, carbon dioxide was used as a cheap and harmless reagent for the synthesis of organic carbamates in the gaseous or supercritical state, or in an electrochemical process, or organic carbonates as sources of carbon dioxide as an alternative to the harmful reagents. The present review will deal with the extensive use of carbon dioxide in the synthesis of organic carbamates.     

Selective reduction of organic compounds with Al-acetoxy- and Al-trifluoroacetoxydiisobutylalane

The new MPV-type reagents, Al-acetoxydiisobutylalane (DIBAOAc) and Al-trifluoroacetoxydiisobutylalane (DIBAO₂CCF₃), have been prepared and their reducing characteristics in the reduction of selected organic compounds containing representative functional groups have been examined in order to find out a new reducing system with unique applicability in organic synthesis. In general, the reactivity of DIBAO₂CCF₃ appears to be much stronger than that of DIBAOAc, presumably due to the acidity increase by the electron-withdrawing fluorine-substituent. Both reagents reduce aldehydes and ketones relatively slowly, but show an excellent selectivity in 1,2-reduction of α,β-unsaturated carbonyl compounds to produce the corresponding allylic alcohols in an absolutely 100% purity. In addition, the reagents achieve the regioselective cleavage of phenyl- or alkyl-substituted epoxides to the less substituted alcohols in an excellent selectivity. Moreover, both reagents show interesting features in the stereoreduction of cyclic ketones. However, these reagents show a very low or/and no reactivity toward most organic functional groups other than carbonyl and epoxy function.     

Transition Metals in the Synthesis and Functionalization of Indoles [New Synthesis Methods (72)]

The use of transition-metal complexes as reagents for the synthesis of complex organic compounds has been under development for at least several decades, and many extraordinary organic transformations of profound potential have been realized. However, adoption of this chemistry by the practicing synthetic organic chemist has been inordinately slow, and only now are transition-metal reagents beginning to achieve their rightful place in the arsenal of organic synthesis. Several factors contributed to the initial reluctance of synthetic organic chemists to use organometallic reagents. Lacking education and experience in the ways of elements having d electrons, synthetic chemists viewed organometallic processes as something mysterious and unpredictable, and not to be discussed in polite society. Organometallic chemists did not help matters by advertising their latest advances as useful synthetic methodology, but restricting their studies to very simple organic systems lacking any serious functionality (e.g., the “methyl, ethyl, butyl, futile” syndrome). Happily, things have changed. Organometallic chemists have turned their attention to more complex systems, and more recently trained organic chemists have benefited from exposure to the application of transition metals. This combination has set the stage for major advances in the use of transition metals in the synthesis of complex organic compounds. This review deals with one aspect of this area, the use of transition metals in the synthesis of indoles.     

Detection reagents used for on-plate identification of organic pesticides in biological samples with preliminary separation by TLC/HPTLC

Many specific and non-specific chromogenic spray reagents have been used to detect organic pesticides (organophosphorus, organochlorine, carbamates, and pyrethroids) on thin-layer chromatographic (TLC)/high-performance thin-layer chromatographic (HPTLC) plates. To realize high sensitivity and improved selectivity, several chromogenic reagents have been introduced. The physical properties of organic pesticides reported so far are also presented in tabular form. The colors produced on TLC plates due to reactions taking place between pesticides and spray reagents are illustrated in the form of chromatograms, and reaction mechanism is also presented.

     

Properties and construction of azo-dye reagents for inorganic photometric analysis

An approach to constructing new organic reagents (based on azo dyes) for photometric analysis is described. Its essence is the detailed consideration of the electronic structure of the chromophore nuclei of the dyes in the ground and excited states. Knowing the nature of the electron transition, it is possible to construct the organic reagents with optimal properties. The electronic structure of the azo dyes has been analysed in a pi-approximation by an MO LCAO SCF method.     

Molecular Lamps and Molecular Golf Balls

The concave shielding of the active site of enzymes has been transferred to standard reagents of organic chemistry and concave reagents have been synthesized which possess a lamp-like geometry (concave 1,10-phenanthrolines 1–2, concave pyridines 3). The special concave geometry of these reagents is responsible for their selectivity in metal ion catalyzed (Pd-catalyzed allylations, Cu(I)-catalyzed cyclopropanations) and base catalyzed (acylation of alcohols by ketenes) reactions. For an easier recovery, these reagents have been attached to Merrifield polymers and to dendrimers. Higher generations of dendrimers loaded with concave reagents will possess a golf ball geometry.