反胶束萃取醇脱氢酶的研究

本文报道了用反胶束体系萃取醇脱氢酶(ADH)的研究结果。在此萃取体系中,以十六烷基三甲基溴化铵(CTAB)作为表面活性剂,辛烷和己醇作为溶剂及助溶剂。考察了振荡时间、水相pH值和离子强度、表面活性剂及助溶剂浓度等因素对醇脱氢酶萃取率的影响,确定了最佳萃取条件。     

反胶束固定化醇脱氢酶的制备及应用研究

研究十六烷基三甲基溴化铵(CTAB)-辛烷-己醇反胶束体系固定化醇脱氢酶(ADH)的制备及应用。考察了含水量、CTAB和己醇用量对于ADH固定化的影响。对游离酶和固定化酶的催化动力学性质研究表明:酶促反应的最适pH值分别为8.2和8.8,最适温度分别为31℃和20℃,米氏常数分别为12mmol/L和7mmol/L。30℃时,游离酶存放150min后失活90%,固定化酶失活50%,表明反胶束固定化ADH有较好的热稳定性。应用此体系测定了试样中乙醇的含量。     

醇脱氢酶在反胶束溶液中的酶学性质研究

以十六烷基三甲基溴化铵(CATB)-辛烷-戊醇反胶束体系对醇脱氢酶(ADH)进行固定化,考察了pH、含水量、表面活性剂和助溶剂浓度对ADH固定化的影响。对游离酶和固定化酶的催化动力学性质研究表明:酶促反应的最适pH值均为9.0,最适温度分别是28℃和20℃,对乙醇的米氏常数分别为8.8mmol/L和5.5mmol/L。25℃时,游离酶存放120min约失活90%,而固定化酶仅失活30%,表明反胶束固定化ADH具有较好的热稳定性。     

醇脱氢酶在反胶束溶液中的催化动力学性质

以十六烷基三甲基溴化铵(CATB)-辛烷-己醇反胶束体系对醇脱氢酶(ADH)进行固定化,试验了含水量、酶液pH值、CTAB和己醇浓度对ADH固定化的影响。对游离酶和固定化酶的催化动力学性质研究表明：酶促反应的最适pH值分别为8.2和8.8,最适温度分别是31℃和20℃,对乙醇的米氏常数Km分别为12mmol/L和7.4mmol/L。在30℃时,游离酶存放150min后失活90%,固定化酶失活50%,表明反胶束固定化ADH有较好的热稳定性。     

伯胺N1923萃取体系反胶束的形成研究

伯胺 N1 92 3是重要的国产萃取剂 ,其经酸化后生成的铵盐在有机相中可聚集形成反向胶束或微乳液[1] ,但在盐酸和硫氰酸等一元酸介质中萃取金属时 ,萃取剂的聚集现象对萃取机理影响不大 ,可用斜率法分析实验结果 ,确定萃合物组成 [2 ] .而在硫酸介质中却表现出特殊的萃取现象 ,发生胶束萃取[3] .对此 ,本文试图从表面与胶体化学的角度对伯胺萃取体系反胶束的形成作深入研究 ,以期对伯胺萃取体系的萃取机理获得更深入的了解 .1　实验部分1 .1　试剂与仪器　伯胺 N1 92 3( RNH2 ) ,平均分子量 2 91 .8(中国科学院上海有机化学研究所实验厂 ) …     

十二烷基苯磺酸钠-异辛烷-正辛醇反胶束萃取苦参生物碱的研究

利用阴离子表面活性剂十二烷基苯磺酸钠(SDBS)与溶剂异辛烷和助溶剂正辛醇形成反胶束体系,用于苦参生物碱的萃取分离。研究了pH值、表面活性剂浓度、增溶水量W0、盐种类及浓度等因素对萃取的影响。结果表明:SDBS-异辛烷-正辛醇反胶束体系对苦参生物碱具有良好的选择性和较高萃取率,在pH 5.0,增溶水量W0 25,0.05 mol/L SDBS,0.05 mol/L KCl,室温,萃取时间5 min,反萃取时间20 min的最佳萃取条件下,氧化苦参碱、氧化槐果碱、槐定碱、苦参碱、槐果碱5种生物碱及总生物碱的萃取率和RSD分别在74.1%～87.2%和0.63%～3.0%之间。本方法选择性高,操作简便。     

两种反胶束固定化酶的催化性质研究

探讨十六烷基三甲基氯化铵(CATC)-戊醇-辛烷反胶束体系固定化乳酸脱氢酶(LDH)和醇脱氢酶(ADH)的催化作用。试验了含水量、表面活性剂以及助溶剂浓度对于酶固载量的影响。对游离酶和固定化酶催化性质研究表明:LDH酶促反应的适宜p H值分别为9.2和9.0,适宜温度为51℃和29℃,米氏常数15mmol·L-1和2mmol·L-1;ADH酶促反应的适宜p H值为8.8和8.2,适宜温度为33℃和39℃,米氏常数4mmol·L-1和17mmol·L-1。应用反胶束固定化酶测定了试样中微量组分。     

反胶束萃取分离生物分子及相关领域的研究进展

综述了反胶束有关的概念、理论；反胶束萃取蛋白质的传质机制、选择性分离过程及工艺流程；反胶束对氨基酸、抗生素及核酸的萃取分离；反胶束与其他方法、技术相结合的应用状况。     

反胶束萃取-高效液相色谱法测定磺酸型偶氮染料

建立了水中磺酸偶氮染料甲基橙（MO）、刚果红（CR）和酸性铬兰K（ACBK）的反胶束萃取-离子对高效液相色谱定量检测的方法。采用Hypersil C18柱（250×4．6mm,5μm）,流动相为V（甲醇）／V（水）=63：37（含10mmol／L的KH2PO4、4mmol／L的四丁基溴化铵,KOH调pH=7．0）,流速为0.8mL／min,MO、CR和ACBK检测波长分别为449nm、505nm和526nm。结果表明,染料的回收率为92．9％～102．1％,相对标准偏差为0．9％～2．3％,水中MO、CR和ACBK的检出限分别为0．6μg／L、1．2μg／L和1．3μg／L。     

反胶束体系中合成聚苯胺-无机物复合纳米微粒

利用阴离子型表面活性剂2-乙基己基琥珀酸钠(AOT)形成的反胶束作为微反应器合成了聚苯胺-氯化银和聚苯胺-硫酸钡复合纳米粒子;考察了搅拌因素和不同合成步骤对聚苯胺-硫酸钡尺寸及形态的影响;并利用TEM, IR, UV-vis, XRD和四探针电导率仪对产物进行了表征.研究结果表明,反胶束法可以有效地应用于有机-无机复合纳米材料的制备.     

硫酸铵-溴化钾铵-正丙醇体系萃取分离和富集锗的研究

研究了硫酸铵-溴化钾铵-正丙醇体系萃取分离和富集锗的行为及与一些金属离子分离的条件.硫酸铵能使正丙醇的水溶液分成两相,在分相过程中,Ge4+与KBr生成(GeBr62-),并与质子化正丙醇(C3H7OH2+)形成缔合物[GeBr62-][C3H7OH2+]2,此缔合物能被正丙醇相完全萃取.当正丙醇、KBr和硫酸铵的浓度分别为30％(V/V)、7.0×10-3mol/L、0.20g/mL时,(GeBr62-)的萃取率达到97.7％以上,而Ni2,Pb2,Cr3+,Co2,Fe3+,Al3+,Mg2+,Ag+,Bi3+,CH2,W(Ⅵ)和V(Ⅴ)基本不被萃取,实现了Ge4+与上述金属离子的分离.     

从酵母细胞中分离纯化醇脱氢酶

醇脱氢酶(ADH)用于食品工业，还是酶法测定乙醇或乙醛含量的工具酶。沉淀法和层析法至今仍然广泛用于分离蛋白质和酶。用离子交换层析、亲和层析等方法经过4～5个纯化步骤后，分离纯化ADH和其它蛋白质，纯化倍数可达100多倍。我们从酵母细胞中分离出醇脱氢酶，并通过硫酸铵分段盐析、凝胶层析以及离子交换层析对该酶进行纯化，用较少的步骤得到了相对高的纯化倍数。     

Effect of Ionic Surfactants on the Adsorption of Quercus infectoria Natural Dye on Cotton Fiber: A Kinetic Study

The adsorption kinetics of Quercus infectoria natural dye on cotton in the absence and presence of the cationic (cetyl trimethyl ammonium bromide; CTAB) and anionic (sodium lauryl sulfate; NaLS) surfactants has been investigated at three temperatures, namely, 40°C, 50°C, and 60°C. On increasing the surfactant content in the surfactant-dye mixture, the initial rate of adsorption (h _i) and the adsorption capacity at equilibrium (q _e) were found to increase while pseudo-second-order rate constant (k ₂) was found to decrease. The retarding effect of surfactant on k ₂ was in order of CTAB > NaLS. The activation parameters for adsorption process have been evaluated in each case, and the mechanism of adsorption process has been discussed.     

四丁基溴化铵-KI-水体系浮选分离钯(Ⅱ)的研究

研究了四丁基溴化铵-KI体系分离钯的行为及与其他金属离子分离的条件。实验结果表明,在水溶液中,Pd(Ⅱ)与四丁基溴化铵和KI形成不溶于水的三元缔合物[PdI4][TBAB]2,此三元缔合物沉淀浮于盐水相上层形成界面清晰的液-固两相。当四丁基溴化铵和KI的浓度分别为7.0×10-4mol/L和2.0×10-3mol/L时,Pd(Ⅱ)的浮选率达到99.5%以上。而Ce(Ⅲ),Fe(Ⅱ),Sn(Ⅳ),Co(Ⅱ),Mn(Ⅱ),Rh(Ⅲ),Zn(Ⅱ),Ga(Ⅲ),Cr(Ⅲ),Mo(Ⅵ),W(Ⅵ),Ni(Ⅱ),Al(Ⅲ)和V(Ⅴ)离子在该体系中不被浮选,实现了Pd(Ⅱ)与这些金属离子的定量分离。对合成水样中Pd(Ⅱ)的分离和测定,结果满意。该方法在微量钯的分离和富集分析中有一定的实用价值。     

Polarographic Determination of Glycyrrhizic Acid Based on Double Enhancement Action of Surfactant and Dissolved Oxygen

ABSTRACT

A method for the determination of glycyrrhizic acid (GA) is described based on polarographic current of GA enhanced doubly by both cation surfactant (cetyl trimethyl ammonium bromide (CTMAB)), and dissolved oxygen (including oxygen-derived species). The doubly enhanced current of GA includes two additional currents. One is the increased reduction current of adsorbed GA induced by CTMAB. The other is the catalytic current of GA caused by the dissolved oxygen molecule and its derived species. In 0.1 M NaAc-Hac (pH4.7±0.1) ～ 1x10^?5 M CTMAB supporting electrolyte without deoxygenation, the enhanced current of GA is linearly proportional to its concentration in the range of 4x10^?7 M ～ 4.0x10^?6 M. The detection limit is 1.8x10^?7 M. The double enhanced current of GA in sensitivity is about 15 times higher than its reduction wave in the same acetate buffer solution.     

Fluorescence enhancement effect for the determination of DNA with calcein-cetyl trimethyl ammonium bromide system

A new spectrofluorimetric method was developed for the determination of trace amounts of DNA using the calcein as a fluorescent probe. In the presence of appropriate amounts of the cationic surfactant cetyl trimethyl ammonium bromide (CTAB), the anionic dye calcein dimerizes. The weak fluorescence intensity of the dimer was enhanced by adding DNA at pH 6–7. The interaction between calcein–CTAB and DNA was studied on the basis of this behavior and a new method was developed for determining DNA. Under the optimal conditions, the enhanced fluorescence intensity was in proportion to the concentration of DNA in the range of 4.0 × 10⁻⁶ to 8.0 × 10⁻⁵ g L⁻¹ for fsDNA and thermally denatured ctDNA (4.5 × 10⁻⁶ to 9.0 × 10⁻⁵ g L⁻¹). The detection limits (S/N = 3) were 2.0 × 10⁻⁶ and 2.2 × 10⁻⁶ g L⁻¹, respectively. This method was used for determining the concentration of DNA in synthetic samples with satisfactory results.     

Effect of polyvinyl alcohol on rare earths (Gd and Tb) separation by extraction resin

Small amounts of polyvinyl alcohol (PVA; 0.5-1.5 wt.%) added to extraction resin was synthesized by suspension polymerization. Their effects on the separation of rare earths (RE) were then investigated by conducting a relative comparison with the performance of pure extraction resin. The supporter and extractant of extraction resin were styrene-divinyl benzene copolymer and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (HEH[EHP]), respectively. The size of PVA added extraction resin was reduced by 40% particle size of pure extraction resin. Furthermore, a higher level of PVA addition, shorter effluent range and smaller resolution values were shown in the extraction. In constant PVA added extraction resin, more diluted effluent concentration, longer effluent range and bigger resolution values were shown in the extraction. This could be the result of the bonding force between the rare earths and the extraction resin due to the nature of the interaction between the OH⁻ group in PVA and the OH⁻ group in extractants such as HEH[EHP]. Thus, the bonding force between the RE and extractants was determined by the level of PVA in the resins and the acidity of the effluent solution became another important factor in the extraction performance of the rare earths. As a result, the optimal level of PVA addition and the concentration of effluent for RE (Gd and Tb) separation were determined to be 0.5 wt.% of PVA and 0.05 M HCl of effluent, respectively.     

KBr-乙醇-(NH_4)_2SO_4体系析相萃取分离和富集铱的研究

研究了KBr-乙醇-(NH_4)_2SO_4水体系析相萃取分离和富集铱的行为及与一些金属离子分离的条件.结果表明,(NH_4)_2SO_4能使乙醇的水溶液分成两相,在分相过程中,Ir(Ⅳ)与KBr生成的IrBr_6~(2-)与质子化乙醇(C_2H_5OH~(2+))形成的缔合物[IrBr_6~(2-)][C_2H_5OH~(2+)]_2能被乙醇相完全萃取.当乙醇、KBr和(NH_4)_2SO_4分别为体积分数30%、4.0×10~(-3)mol/J L、0.3 g,mL.pH 3时,Ir(Ⅳ)的萃取率达到99.5%以上,Ga(Ⅲ),Al(Ⅲ),Cr(Ⅲ),Mo(Ⅵ),Fe(Ⅲ),Ni(Ⅱ),Zn(Ⅱ),Co(Ⅱ),Mn(Ⅱ),V(Ⅴ),Ag(Ⅰ),Ru(Ⅲ)和Rh(Ⅲ)基本不被萃取,实现了Ir(Ⅳ)与上述金属离子的分离.     

阳离子表面活性剂R16HTAB及其复配体系的流变性能

用稳态和动态流变学方法研究了3-十六烷氧基-2-羟丙基三甲基溴化铵（R16HTAB）单纯以及水杨酸钠（NaSal）存在下溶液的流变特性．无盐体系中,在测定的浓度范围内,表面活性剂与零剪切黏度呈指数关系（η0∝c^2．53）．水杨酸钠的加入促进了体系由球状向蠕虫状胶束转化．Cox—Merz规则和Cole-Cole图证明,混合体系生成了蠕虫状胶束．与传统的CTAB比较,无论水杨酸钠存在与否,R16HTAB水溶液的流变性能均较好,这主要归因于羟丙基基团的插入,使得R16HTAB和NaSal分子之间形成氢键连接,生成了更加稳定的三维网络结构．应用冷冻蚀刻电子显微镜技术进一步证实了体系中蠕虫状胶柬的存在．     

Determination of breath alcohol using a differential-type amperometric biosensor based on alcohol dehydrogenase

A differential-type amperometric biosensor based on conventional thick-film technology has been developed for breath alcohol measurement. The amperometric breath alcohol biosensor utilizes the alcohol dehydrogenase (ADH) and nicotinamide adenine dinucleotide (NAD⁺) cofactor which produce reduced NADH as a product of the oxidation of alcohol. The biosensor was designed in a differential format consisting of a common Ag/AgCl reference electrode, an active working electrode containing the ADH, and the inactive working electrode containing only bovine serum albumin instead of the ADH. The differential signal between the active working electrode and the inactive working electrode minimized the interference from a large number of oxidizable species present in a person's breath. Prior to the amperometric measurement the biosensor was hydrated simply by dipping it into a phosphate buffer solution at pH 7.4. The NADH produced from the enzymatic reaction was oxidized at the working electrode biased at a potential of 470 mV vs. an on-board Ag/AgCl reference electrode. The biosensor can measure a person's breath alcohol over the concentration range 20–800 ppm routinely required in a test of drunken driving.