C3H+与N反应的理论研究

用密度泛函方法在QCISD(T)／6—311 G^**//B3LYP／6—311G^*水平上研究了气相反应C3H^ N的反应机理．得到了不同能量产物的可能的反应通道，获得反应势能面．整个反应为多通道反应，经过多个步骤完成，共找到9个中间体和11个过渡态，产物C3H^ N(P2)为能量较低的产物，通道3：IM5→TS4→IM6→TS5→IM7→TS7→IM8→P2为较为可行的反应通道．     

不对称变色酸双偶氮氟胂型新显色剂的合成及其与钍的显色反应研究

合成了8种不对称变色酸双偶氮氟胂型新显色剂，并研究了它们与钍的显色反应，建立了最佳反应体系。试验发现由于引入了吸电子性极强的氟取代基，反应体系的酸度、选择性及灵敏度大为提高，是一组很好的测钍显色剂。     

拓扑指数法研究显色剂结构与反应性能关系

本文讨论了２９个不对称色酸双偶氮膦酸型显色剂的分子联接性指数，并将其与结构选择性因子相结合，用于偶氮类剂结构与铈显色反应灵敏度的相关性研究，讨论了显色剂结构对显色反应灵敏度的影响。     

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。     

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。     

CH_3自由基和O（~3P）反应机理的量子化学研究

用分子轨道从头计算MP2（full）方法和密度泛函理论（DFT）中的B3LYP方法 研究了CH_3自由基和三线态O原子反应的微观机理，优化得到了反应途径上的反应 物、过渡态、中间体和产物的几何构型，通过振动分析对过渡态和中间体构型进行 了确认，在G3不平上计算了能量，同时用经典过渡态理论对该反应的绝对速率常数 进行了理论计算。研究结果表明：CH_3自由基与O（~3P）反应有四条不同的放热反 应通道，主反应通道为IM1→TS1→CH_2O + H，同时反应可彻底裂解生成CO, H_2 及H。     

CH_2CH(~2A')自由基与臭氧反应机理的理论研究

用量子化学MP2（full）方法，在6－311+ +G~(**)基组水平上研究了CH_2CH (~2A~＇)自由基与臭氧反应的机理，全参数优化了反应过程中反应物、中间体、过 渡态和产物的几何构型，在QCISD（T,full）/6-311+ +G~(**)水平上计算了它们的 能量，并对它们进行了振动分析，以确定中间体和过渡态的真实性，研究结果表明 ：CH_2CH(~2A~＇)自由基与臭氧反应有两条可行的反应通道，分别为：CH_2CH (~2A~＇)+O_3→TS1→M1→TS2→O_2+OCH_2CH→TS4+O_2→O_2(~3∑_g)+CH_2CHO (~2A~＂)和CH_2CH(~2A~＇)+O_3→M2→TS3→O_2(~3∑_g)+CHO(~2A~＂),后一个反 应通道较容易发生，而且反应活化能小（2.97kJ/mol），说明CH_2CH(~2A~＇)自由 基与臭氧之间的反应活性很强。     

CH3O2·+ClO气相反应的密度泛函理论研究

用密度泛函方法在CCSD(T)/ 6-311++G// B3LYP/ 6-311G**水平上研究了气相反应CH3O2*+ClO的反应机理.得到了不同能量产物的可能的反应通道,获得反应势能面.整个反应过程为多通道反应,经过多个步骤完成,共找到7个中间体和10个过渡态,产物1CH3OCl+3O2(P1)和1 CH2O+1HOOCl(P4)为能量较低产物,通道1a:R→IM1→TS1/ 3→IM3→P1,4a:R→IM1→TS1/ P4→P4和4b:R→IM2→TS2/ P4→P4为较为可行的反应通道.     

碱土金属与多卤代偶氮氯膦类试剂显色反应的研究

近年来合成的多卤代偶氮氯膦类试剂有希望成为一类有效的碱土金属显色剂。本文研究了此类试剂与钙、锶、钡所生成配合物的吸收光谱、显色酸度、选择性、灵敏度和配合物的组成,以及试剂结构与性能的关系等。说明了不同取代助色基对显色反应各方面的影响。通过研究筛选出了较好的碱土显色剂,这几种试剂的结构如下:     

Mo活化NH3的自旋禁阻反应机理

采用密度泛函理论的UB3LYP方法,计算研究了气相中Mo活化NH3的反应机理。为了理解由Mo活化NH3过程中自旋翻转行为,对自旋态分别为七、五、三和单等4个反应势能面进行了计算研究,其结果表明,Mo活化NH3的过程是通过各自旋态势能面交叉产生的典型的自旋禁阻反应,最低能量交叉点(MECPs)附近的系间窜越导致2步H转移和脱H2反应能垒降低。此外运用自然键(NBO)轨道理论分析了反应中较为重要的几个物种的成键特性。通过计算在最低能量交叉点(MECPs)附近不同自旋态之间的自旋-轨道耦合常数,再运用Landau-Zener跃迁几率公式估算了MECPs处系间窜越几率。所确定的最低能量反应路径为:7Mo+NH3→7IM1→7/5MECP1→5TS12→5IM2→5/3MECP2→3TS23→3IM3→3TS34→3IM4→3HMoN+H2。     

牛血清白蛋白与光谱探针相互作用机理的研究

在酸性条件下研究了考马斯亮蓝光谱探针与牛血清白蛋白结合物的光学性质,探讨了考马斯亮蓝染料和蛋白质的相互作用机理。研究结果表明染料考马斯亮蓝的疏水作用和亲水作用的协调作用以及与生物大分子蛋白质具有相反电荷的静电作用,是光谱探针与生物大分子形成大分子聚集体的必要因素。     

Langmuir Aggregation of Coomassie Brill Blue on Protein and Determination of Protein by MPASC

The microphase adsorption–spectral correction technique (MPASC) has been applied to investigate the aggregation of coormassie brill blue G250 (CBBG) on protein in which the microelectrostatic fields exist. The Langmuir adsorption of CBBG in protein was confirmed, and the interaction is sensitive at pH 3.78. Results show that the adsorption ratio of CBBG to five proteins, e.g., BSA, OVA, Hb, Mb and -G are 100, 65, 30, 98 and 210, respectively, their adsorption constants are 9.92 × 10⁴, 8.04 x 10⁴, 9.38 × 10⁴, 1.66 × 10⁵, and 2.75 × 10⁴, and their absorptivities are 2.33 × 10⁶, 1.56 × 10⁶, 1.98 × 10⁶, 5.61 × 10⁵, and 4.48 × 10⁶ Lmol^–1 at 670 nm. The study indicates that 1 mg of protein adsorbs about 1.54 mmol of CBBG. For the protein determination of samples, the recovery of protein is between 88.0 and 111% and the relative standard deviation is 2.6%.     

流动注射分光光度法快速测定乳制品中的蛋白质含量

建立了快速测定乳制品中真蛋白质含量的交替合并带异步注入流动注射分光光度法.样品和试剂自动同时定量,分别同时被注入到超纯水和缓冲液中,以合并带中试样包裹试剂的方式进行汇合、反应,生成的蓝色络合物进入流通检测器,在595 nm下进行定量分析.得到的最佳测定条件为:反应试剂中考马斯亮蓝的浓度为150 mg/L,缓冲液中HCI...     

Study of the formation of dye-induced premicellar aggregates and its application to the determination of quaternary ammonium surfactants

Formation of dye-induced mixed premicellar aggregates from binary surfactant solutions is proposed for the determination of alkyltrimethylammonium surfactants at the muM level. The Coomassie Brilliant Blue G (CBBG) dye, negatively charged, induces the formation of cationic surfactant aggregates at concentrations far below the cmc. The role of CBBG in the formation of premicelles was studied by using pyrene as a fluorimetric probe. Formation of CBBG-cationic surfactant aggregates of well-defined stoichiometries that depend on the total surfactant concentration added is demonstrated. Also, the influence of analytical parameters affecting the concentration at which a given aggregate is formed was studied. Linear calibrations for alkyltrimethylammonium surfactants were obtained by using different cationic surfactants as titrants; therefore, the previously derived measurement parameter for mixed micelles is applicable to premicellar aggregates as well.     

Determination of aromatic hydrotropic drugs in pharmaceutical preparations by the surfactant-binding degree method

An aggregation parameter-based analytical approach, the surfactant-dye binding degree (SDBD) method, was used, for the first time, to determine aromatic hydrotropic compounds. The anionic dye Coomassie Brilliant Blue G (CBBG) was used as inductor of didodecyldimethylammonium bromide (DDABr) aggregates, whose formation was monitored from changes in the spectral features of the dye. Interactions between hydrotrope and DDABr molecules resulted in a decrease of the degree of binding of the cationic surfactant to CBBG, which was proportional to the concentration of hydrotrope in the aqueous solution. The CBBG-DDABr-hydrotrope chemical system was found to fit to the mathematical expression previously derived for the determination of amphiphilic compounds. The hydrotrope-surfactant bond strength determined the sensitivity achieved for the determination of hydrotropic compounds, which was highly dependent on the molecular structure of the analyte. The high precision (the relative standard deviation for 7 mg l(-1) of salicylic acid was 0.8%), rapidity (measurements were performed in a few minutes) and low cost (in both instrumentation and reactants) of the proposed method, made it especially suitable for quality control. The practical analytical applicability of the SDBD method for the control of hydrotropic drugs in pharmaceutical preparations was demonstrated by quantifying salicylic acid and acetyl salicylic acid in liquid (solutions) and solid (tablets, granulates, unguents, gels and creams) samples, which were directly analyzed after dissolution of the samples.     

Surfactant to dye binding degree based approach for the selective determination of l-glutamate in foodstuffs

A selective method for the determination of l-glutamate in foodstuffs has been developed. It was based on the competition established between the analyte and the dye Coomassie brilliant blue G (CBBG) to interact with the surfactant didodecyldimethylammonium bromide (DDABr). The measurement parameter was the amount of DDABr required to reach a given dye-to-surfactant binding degree. It was obtained by photometric titration on the basis of the changes observed in the spectral characteristics of the dye when CBBG–DDABr aggregates were formed. The calibration graph obtained was linear in the l-glutamate concentration interval 0.2–5 mM (detection limit 0.05 mM). The high selectivity of the proposed method (other amino acids and food additives did not interfere at the concentrations present in foodstuffs) permitted the direct analysis of food samples after dissolution of the analyte in hot water. The accuracy of the surfactant to the dye binding degree method was demonstrated by determining l-glutamate in different kinds of foodstuffs (liquid and dried soups, seasonings, pasta sauces and dried mushroom creams) and comparing the results obtained with those provided by the commercial Boehringer Mannheim essay.     

Cu（Ⅱ）-H2O2-考马斯亮蓝G250体系催化光度法测定痕量铜

在NH3-NH4Cl缓冲溶液介质中,痕量Cu2+对H2O2氧化考马斯亮蓝G250(CBBG)褪色反应的显著催化作用,建立了催化动力学光度法测定痕量铜的新方法。线性范围为0.02～0.20μg/mL,检出限为1.34×10-9g/mL。考察了20多种共存离子的影响。方法用于发样中痕量铜离子的测定,相对标准偏差小于3.4%,加标回收率为97%～105%。     

Assessment of the surfactant-dye binding degree method as an alternative to the methylene blue method for the determination of anionic surfactants in aqueous environmental samples

The surfactant to dye binding degree (SDBD) method is proposed for the routine monitoring of anionic surfactants in aqueous environmental samples and their analytical features compared with those provided by the standard methylene blue (MB) method. This new analytical approach is based on the effect that anionic surfactants exert on the binding degree of the cationic surfactant didodecyldimethylammonium bromide (DDABr) to the anionic dye Coomassie Brilliant Blue G (CBBG). The formation of DDABr-CBBG aggregates is monitored photometrically. The analytical applicability of the proposed method was demonstrated by determining anionic surfactants in tap, river and swamp water, and raw and treated sewage. The mean recoveries obtained ranged between 99 and 101%. The SDBD method offers important advantages over the classical MB method: it is more sensitive, selective, precise, simple and rapid; the analytical response is independent of the molecular structure of the anionic surfactants, and the volume of sample required for analysis and the consumption of organic solvents are significantly reduced.     

Determination of dialkyldimethylammonium surfactants in sewage based on the formation of premicellar aggregates

A method is described for the determination of dialkyldimethylammonium surfactants (DDAS) in sewage, based on the formation of premicellar aggregates with sodium dodecyl sulfate and using the dye Coomassie Brilliant Blue G (CBBG) as a photometric probe. The mixed aggregates are selectively obtained at DDAS concentrations three orders of magnitude below the critical micelle concentration. As a result, DDAS can be determined at the microg l(-1) level without interference from other quaternary ammonium/pyridinium or anionic/non-ionic surfactants. Because of the selectivity of the method, the clean-up of sewage influents and effluents only involves extraction with chloroform, after formation of the DDAS-sodium dodecane sulfonic acid ion pair, evaporation of the extracts to dryness and dissolution of DDAS in 4 M hydrochloric acid. The recovery of DDAS ranged from 82 to 93% and from 100 to 105% in sewage influents and effluents, respectively.