二茂铁表面活性剂电化学行为的胶束效应

采用循环伏安法研究了具有可逆特性的二茂铁表面活性剂Fc12在pH值为2的0.1 mol·L-1 Li2SO4溶液中的电化学行为的胶束效应,讨论了扫描速度及底物浓度对Fc12电化学行为的影响.结果表明,Fc12具有良好的可逆变化特性,可在氧化态(I2+)与还原态(I+)之间实现自由转换; Fc12在玻碳电极上的峰电流(Ipc)与扫描速度的平方根呈线性关系(R=0.997),说明Fc12的电化学行为是受扩散控制的可逆过程;Ipc和扩散系数(D)在Fc12的临界胶束浓度(CMC)附近出现突变,Ipc和D随Fc12单体的浓度变化较快,超过CMC后,Ipc与D随表面活性剂浓度缓慢变化,与Fc12表面张力变化趋势相吻合.     

去甲肾上腺素聚合物的电化学沉积及性质研究

采用循环伏安法研究了金电极上去甲肾上腺素(NA)电氧化形成聚合膜的过程,结合电化学和红外光谱研究提出该聚合膜可能是聚吲哚膜的类似物,且该聚合膜具有较好的阳离子选择透过性。     

石墨烯修饰电极对去甲肾上腺素电分析性能的研究

制备了石墨烯修饰电极,研究了去甲肾上腺素(NE)在修饰电极上的电化学行为,实验结果表明,石墨烯修饰电极对去甲肾上腺素有明显的催化作用。在pH=5的柠檬酸-磷酸氢二钠的缓冲溶液中,NE的氧化峰电流与浓度在9.2×10-7～2.3×10-5mol/L范围内呈线性关系,检出限为4.6×10-8mol/L。修饰电极表现出良好的稳定性。     

银-亮氨酸复合膜修饰电极测定去甲肾上腺素

利用循环伏安法(CV)制备了银和亮氨酸聚合物膜修饰电极(Ag-Leu/GCE)。研究表明,电极对NE的电化学氧化具有明显的催化作用。氧化峰电流与去甲肾上腺素浓度在2.4×10-7~4.8×10-5mol/L范围内呈线性关系,检出限(3S/N)为1.2×10-8mol/L。修饰电极用于药物中去甲肾上腺素的测定,加标回收率在97.5%~101.3%之间。     

二茂铁表面活性剂的合成及其电化学行为研究

合成了具有可逆特性的二茂铁表面活性剂N,N-二甲基二茂铁甲基正辛烷基溴化铵(Fc8),并以玻碳电极为工作电极,采用循环伏安法研究了Fc8在0.1 mol/L NaCl溶液中的电化学行为,讨论了pH、扫描速度及底物浓度对Fc8电化学行为的影响。结果表明,Fc8在pH<8的条件下具有良好的可逆性,可在氧化态(I2+)与还原态(I+)之间实现变换;Fc8在玻碳电极上的氧化峰电流(Ipc)与扫描速度呈现线性关系(R2>0.998),说明Fc8的电化学行为是受扩散控制的可逆过程;Ipc和扩散系数(D)在Fc8的临界胶束浓度(CMC)附近出现突变,在CMC以上,Ipc与D随表面活性剂浓度缓慢变化,该规律与Fc8表面张力变化趋势吻合,表明峰电流和扩散系数随Fc8浓度变化较快。     

酞菁锰仿生催化去甲肾上腺素氧化的研究

采用UV/Vis法,以酞菁锰（MnPc）为催化剂仿生催化去甲肾上腺素（NA）氧化,系统地研究了催化时间、温度、pH和催化剂用量对催化效率的影响,实验结果表明,MnPc能有效地催化NA氧化生成去甲肾上腺素红。     

三甲胺在碳糊电极上的电化学行为及其测定

采用循环伏安法研究了三甲胺在碳糊电极上的电化学氧化行为,在0.1 mol/L KCl溶液中三甲胺在+0.861 V(vs.SCE)出现一个氧化峰。考察了支持电解质用量、扫描速率等条件对三甲胺电化学氧化信号的影响,求解电化学反应相关参数。利用示差脉冲伏安法对三甲胺进行了检测,其氧化峰电流与浓度在4.0×10-4～0.1 mol/L范围内呈良好的线性关系,检测限为3.12×10-4 mol/L(3σ)。     

石墨炉原子吸收光谱法测定重酒石酸去甲肾上腺素中痕量钯

建立了用石墨炉原子吸收光谱法测定重酒石酸去甲肾上腺素中痕量钯的分析方法。方法检出限为0.05ng/mL,精密度为4.0%,回收率为89.30%~102.70%。     

循环伏安法研究显影剂的电化学行为

本文用循环伏安法对几种显影剂及其类似物DEPPD、DEPAP和TEPPD的电化学进行了研究。实验结果证明,DEPPD经一步氧化成醌二亚胺(QDI),而TEPPD则分两步氧化;DEPAP在pH<7时一步氧化成醌亚胺(QMI),pH>7时分两步氧化。在碱性条件下,各氧化产物可发生明显的脱氨反应。由实验测得的E 1/2与pH的关系,估算了它们的去质子化常数。     

孔雀石绿的电化学行为研究及应用

在HAc—NaAc缓冲溶液（pH=4．0）中,孔雀石绿在-0．745V（vs．SCE）处有一灵敏的极谱还原波,用单扫描示波极谱法建立了测定孔雀石绿的新方法,二阶导数峰电与孔雀石绿浓度在1．27×10^-7～1．78×10^-5mol／L范围内呈线性关系,相关系数为0．9988,检出限为2．54×10^-8mol／L。此法用于水样、土样中微量孔雀石绿的测定,其回收率分别在98．0％。101．2％和71．0％．83．0％。     

Partition Coefficients of Alkyl Parabens and Ibuprofen in Micellar Systems

The partitioning of alkyl parabens and ibuprofen in aqueous solutions of nonionic and ionic surfactants is studied experimentally and via a priori predictions using the COSMO‐RS model. The effects of organic (Bu₄NBr) and inorganic (NaCl) electrolytes are examined. Addition of NaCl results in a slight increase in the partition coefficients of parabens in solutions of octylphenolpoly(ethyleneglycolether) and a more pronounced increase in the sodium dodecyl sulfate (SDS) system. The partition coefficients of ibuprofen increase on addition of NaCl to aqueous solutions of SDS and decrease if Bu₄NBr is added to dodecyl trimethyl ammonium bromide (DTAB) solutions. Good agreement between experimental and calculated data shows a high potential of COSMO‐RS in the prediction of micelle/water partition coefficients in the presence of electrolytes and makes it a valuable tool in drug and drug‐carrier design as well as in optimizing micellar reactions or micelle‐enhanced separation processes.     

煤的电化学氧化研究进展

本文主要介绍国内外近十几年来，煤浆液电化学氧化制取氧气及有机羧酸类产物的研究进展。指出将来实际应用中应该着重解决的若干关键问题和应采取的措施。     

Extraction of Concanavalin A with Affinity Reversed Micellar Systems

Abstract

An affinity reversed micellar system was used for extraction of concanavalin A (con A) with AOT and a biological detergent as the affinity cosurfactant. Six detergents with varying alkyl tail lengths and different head groups were compared for their extraction efficiency of con A. The effects of system parameters such as solution pH, cosurfactant concentration, and the presence of inhibitory saccharides on protein transfer were studied. For glucosides, protein transfer depends on the tail length of the cosurfactant, and the optimum length for maximum protein transfer is eight. A simple thermodynamic model for affinity partitioning of the protein between the two phases can fit the experimental results reasonably well. The estimated association constants for the protein-cosurfactant complex in the micellar phase are consistent with the literature values. For backward transfer of con A from a micellar phase with a stripping aqueous solution, 12.5% isopropyl alcohol addition to the aqueous phase can release the maximum amount of protein (88%). The reversed micelle still maintained its functional integrity after backward transfer, but loss of cosurfactant to the aqueous phase was significant, and reusability of the micellar phase was rather low. Using a more hydrophobic cosurfactant can only partially solve this problem, where spontaneous loss of cosurfactant to the phase interface during protein backward transfer still occurred.     

Electrochemical Investigation of Chalcopyrite Oxidation in Alkaline Solutions

Electrochemical oxidation of chalcopyrite (CuFeS₂) was investigated as an attempt to gain a better understanding of its surface oxidation chemistry in alkaline solutions. Rest potential measurements, cyclic voltammetry and chronoamperometry experiments were conducted in the pH range of 7 to 13 to determine the influence of pH, immersion time, and applied potential on the mineral oxidation state. Rest potential was found to increase by immersion time and oxygen content of the solution and decrease by the pH value. Cyclic voltammetry experiments revealed that the mineral oxidation occurs in three stages. Increase of the pH value caused the peaks to shift to lower potentials. The results were confirmed by chronoamperometry experiments.     

反胶团系统及蛋白质萃取过程研究进展

综述了反胶团系统和蛋白质萃取过程,将反胶团萃取系统按单一反胶团系统、混合反胶团系统和亲和反胶团系统划分,强调了研究开发生物相容性表面活性剂以及在反胶团系统中引入亲和作用的重要性。另外,指出了深入开展反胶团萃取设备和过程研究的必要性。     

Biocatalysis of Chlorophyllase in Ternary Micellar Systems Using Pheophytins as Substrates

The partially purified chlorophyllase, obtained from the alga Phaeodactylum tricornutum, was assayed for its hydrolytic activity towards the pheophytin in ternary micellar systems of hexane/Tris–HCl/surfactant. A wide range of surfactants, sorbitans (Span 20, 40, 60, 80 and 85) and polysorbates (Tween 20, 40, 60, 80 and 85), was used. The use of either 50 μmol dm⁻³ of Span 85 or 1 μmol dm⁻³ of Tween 80 increased the hydrolytic activity of chlorophyllase by 110 and 23%, respectively. The optimum values of pH, enzyme content, incubation time and temperature for the hydrolytic activity of chlorophyllase were determined as 8·25, 8·00 μg protein cm⁻³, 60 min and 27·5°C, respectively. The V_max and K_m values were 6·91 nmole hydrolyzed pheophytin mg⁻¹ protein min⁻¹ and 47·2 nmole pheophytin dm⁻³, respectively, in the Span 85 medium and 10·04 and 121·00, respectively, in the Tween 80 medium. The addition of optimized amounts of individual membrane lipids, L -α-phosphatidylcholine, L -α-phosphatidyl-DL -glycerol and β-carotene increased the hydrolytic activity of chlorophyllase by 50, 36 and 10%, respectively, for Span 85 and 30, 48 and 15%, respectively, for Tween 80. Phytol showed a competitive inhibitory effect on chlorophyllase activity in both Span and Tween systems with a K_i value of 15·5 and 14·3 μmol dm⁻³, respectively. High-performance liquid chromatography and spectrophotometry analyses were used to characterize the end-products of chlorophyllase hydrolytic reaction. © 1997 SCI.     

微晶纤维素的电化学氧化研究

以微晶纤维素为原料、氯化钠为电解质电氧化合成氧化纤维素,采用正交实验法研究了反应温度、pH值、电流密度和反应时间等对产物醛基和羧基含量的影响.结果表明,对产物醛基、羧基影响的顺序是电流密度>反应时间>反应温度>pH值.通过正交实验,得到电化学氧化微晶纤维素的最佳条件为:反应温度30℃、pH值约1.0、电流密度0.032 A·cm-2、反应时间5 h,此时可得到醛基含量为0.936%(质量分数)、羧基含量为2.27%(质量分数)的氧化纤维素.     

电化学氧化煤浆特性研究

采用伏安法对六种煤浆的电解氧化特性进行研究,考察了煤种、铁离子溶液催化剂、温度和搅拌速度对氧化电流密度的影响。结果表明,温度、电压和转速的增加可以提高其氧化电流密度,在室温下加入5 mmol Fe3+,可以使神木煤浆的氧化电流密度提高至18.4 m A/cm2。通过XRD分析可知,电解破坏煤的大分子结构。