亮绿褪色分光光度法测定阴离子表面活性剂

在硫酸介质中,微量阴离子表面活性剂、十二烷基苯磺酸钠、十二烷基磺酸钠、十二烷基硫酸钠能使亮绿产生灵敏的褪色反应,最大褪色波长位于640nm。十二烷基苯磺酸钠、十二烷基磺酸钠、十二烷基硫酸钠的浓度分别在0—6、0—10、0—8mg/L范围符合比耳定律,表观摩尔吸收系数分别为8.89×10~3、4.03×10~3、5.28×10~3L·mol~(-1)·cm~(-1)。该法用于生活废水中微量阴离子表面活性剂的测定,结果满意。     

丝素肽和β-环糊精包合作用及表面活性剂影响

在pH为2和包合时间是60min的最佳条件下,采用光谱法（荧光光谱与紫外-可见光谱）测得β-环糊精（β-CD）与丝素肽构成的包合体系包合比均是2∶1,平均包合常数是3.3×105。两种阴离子表面活性剂十二烷基硫酸钠、十二烷基苯磺酸钠对包合体系有阻抑作用,阳离子表面活性剂十六烷基三甲基溴化铵和非离子表面活性剂＂平平加O＂对包合体系没有影响。     

胶束体系中荧光素与四溴荧光素间能量转移条件及模型研究

研究了阳离子表面活性剂(CSAA)在水溶液中与阴离子酸性染料四溴荧光素(TBF)的荧光反应,发现当CSAA单体与TBF形成离子缔合物时,TBF的荧光发生猝灭,而CSAA胶束与TBF作用又会产生一个新的、更强的荧光。进而研究了阳离子表面活性剂CTMAB及CPB胶束体系中酸性阴离子荧光染料荧光素与四溴荧光素间的能量转移条件。表明只有在带相反电荷的CSAA形成的胶束中,阴离子染料间的能量转移才可能发生,在2/3临界胶束浓度(CMC)时能量转移效率达到最大。并推测了胶束体系中染料间能量转移模型及染料间能量转移的一般规律。     

均匀设计优化共振瑞利散射法测定水中阴离子表面活性剂

在均匀设计优化后的反应条件下,研究了含吩嗪结构类染料健那绿（JG）与十二烷基苯磺酸钠（SDBS）作用的共振瑞利散射光谱,建立一种简便快速的环境水样中阴离子表面活性剂（AS）均匀设计优化共振瑞利散测定新方法。在pH12.4时,加入SDBS导致JG共振瑞利散射剧烈增强,在λem=λex=625nm处,存在一共振瑞利散射峰,其强度与SDBS的浓度呈线性关系,方法的线性范围为0—3.48mg·mL^-1,检出限为17.8ng·mL^-1。方法简便、快速,与单因素轮换法实验结果比较,实验条件更优化,可直接用于测定环境水样中的阴离子表面活性剂。     

SPAPT-CPB-AS光度法测定阴离子表面活性剂

在ＮａＯＨ介质中,新试剂１－（４－磺酸基苯基）－３－「４－（苯基偶氮）苯基」三氮烯（ＳＰＡＰＴ）和溴化十六烷基吡啶（ＣＰＢ）与阴离子表面活性剂（ＡＳ）发生显色反应,形成三元配合物。利用ＳＰＡＰＴ－ＣＰＢ－ＡＳ显色体系。研究了光度法有离子表面活性剂。最大吸收波长５９０ｎｍ,测定十二基苯磺酸钠（ＤＢＯＳＯ３Ｎａ）、十二烷基磺酸钠（ＤＯＳＯ３Ｎａ）、十二烷基硫酸钠（ＤＳＯ４Ｎａ）的表观摩尔吸光系数分别为     

基于荧光光谱技术对常用洗衣粉中表面活性剂含量的测定

十二烷基苯磺酸钠(Sodium Dodecyl Benzene Sulfonate,SDBS)是一种通用的阴离子表面活性剂,其洗涤性能优良,配伍性能好,可与其他无助剂以不同比例配比,且价格便宜,被广泛应用于洗衣粉中。应用FS920荧光光谱仪分析了不同浓度的十二烷基苯磺酸钠水溶液和不同品牌洗衣粉水溶液的荧光光谱特性,发现十二烷基苯磺酸钠溶液的荧光特征峰位于λ_(ex)/λ_(em)=315/350nm,洗衣粉水溶液的荧光特征峰位于λ_(ex)/λ_(em)=356/430nm,经分析是由于洗衣粉中添加了其他非离子表面活性剂、沸石等物质使特征峰发生红移。根据荧光强度与浓度的关系,采用径向基神经网络完成了水溶液中十二烷基苯磺酸钠含量的定量测试,同时通过采用荧光光谱技术和径向基神经网络相结合的检测方法分析了生活中常见的7个常用品牌洗衣粉中表面活性剂的含量。     

光谱法研究吡罗红G与十二烷基硫酸钠的相互作用

为了探讨染料在纺织染色等领域的应用性,采用应用最为广泛的光谱法研究了阴离子表面活性剂十二烷基硫酸钠与吡罗红G的相互作用.发现当阴离子表面活性剂单体与吡罗红G形成缔合物时,荧光发生猝灭;随着表面活性剂浓度的进一步增加,表面活性剂形成的胶束与吡罗红G作用,导致出现一个新的、更强的荧光峰.同时考察了硫酸钠和尿素对二者相互作用...     

丁基罗丹明B-表面活性剂体系荧光光谱法测定人血清蛋白

研究了阳离子染料丁基罗丹明 B在阴离子表面活性剂十二烷基苯磺酸钠存在时的吸收光谱和荧光性能 ,发现随蛋白质浓度增大荧光强度逐渐增强 ,在一定范围内增强程度与蛋白质浓度成正比 ,据此建立了一种测定人血清蛋白的新方法 ,线性范围 0— 6 .0 mg·L-1 ,检出限为 4 .4 μg/ L。用于合成样品测定 ,结果令人满意。     

硫杂杯[4]芳烃基胶束自组装荧光探针的结构性质及检测性能的研究

水体中重金属污染因威胁生态环境和人类健康而被受广泛关注。荧光探针由于具有快速高效检测重金属的特性,一直是该领域的研究热点。通常,荧光探针在结构上包括对待测物质起识别作用的受体和能产生信号响应的荧光体,并逐步形成了内在型、共轭型、系综型和模板辅助自组装型等四种结构类型。近年来,基于受体和荧光体在表面活性剂胶束内自组装而形成的胶束自组装型荧光探针因结构简单、易于制备、能直接应用于水环境等特点逐渐受到重视。以对铜离子具有优异结合性能的对叔丁基硫杂杯[4]芳烃（TCA）为受体,以芘、荧蒽、蒽、菲、苝等分子为荧光体,通过表面活性剂胶束自组装制备针对Cu2+检测的胶束自组装型荧光探针,采用参比法测定了胶束自组装荧光探针的荧光量子产率,采用稳态荧光法测定了胶束聚集数,同时通过计算荧光猝灭率分别考察了荧光体种类、复配表面活性剂等因素对该探针的Cu2+检测性能的影响情况。实验结果显示,采用十二烷基硫酸钠（SDS）、曲拉通100（TX-100）、聚氧乙烯月桂醚（Brij35）等三种不同的表面活性剂对探针荧光体的荧光量子产率产生了明显影响,测得的荧光探针荧光量子产率介于0.25~0.47,且三者逐渐增大,说明表面活性剂改变了胶束内荧光分子芘所处微环境的极性,且不同类型表面活性剂对微环境极性的影响程度有所差异,微环境极性的增强对极性更大的激发态芘具有更强的稳定作用。而受体TCA的加入对荧光体所处微环境极性影响较小,未对荧光量子产率产生较大影响。但TCA的加入使探针的胶束聚集数明显减少,这归因于具有两亲性的受体TCA分子通过胶束自组装进入并分散在表面活性剂分子层中,形成共胶束结构,从而改变了表面活性剂分子的聚集状态。荧光体变更对荧光探针的Cu2+检测性能有显著影响,在同样条件下,以荧蒽、蒽、菲作为荧光体的探针检测Cu2+所得到的荧光猝灭率远高于芘、苝,这主要是因为不同荧光体在从激发态返回基态时辐射跃迁所释放能量不同,其能量与受体TCA识别Cu2+所需能量之间的匹配度越高,荧光猝灭率越大。不同类型的表面活性剂之间的复配能明显提升荧光探针检测性能,当非离子/阴离子、非离子/阳离子型复配表面活性剂之间的复配比例分别为7∶3和1∶1时荧光猝灭率达到最大值,且均高于单一表面活性剂时的荧光猝灭率。这说明不同类型表面活性剂复配的最佳比例存在较大差异,但均有效地增强了受体与荧光体的分散性及自组装性能,提高了对Cu2+的检测性能。研究结果将为新型胶束自组装荧光探针的设计和应用提供数据参考。     

吖啶橙与表面活性剂的作用及其在测定蛋白质中的应用

运用紫外光谱法和荧光光谱法研究了染料吖啶橙中加入表面活性剂十二烷基苯磺酸钠以及牛血清白蛋白后紫外光谱和荧光光谱的变化情况。以吖啶橙在十二烷基苯磺酸钠中生成的二聚体作为荧光探针,讨论了与牛血清白蛋白相互作用情况。采用荧光呈现法对牛血清白蛋白进行了测定,结果表明,该方法反应灵敏,速度快,线性范围为0～4.17×10-7 mol·L-1, 相对标准偏差为1.9%, 检出限为8.73×10-10 mol·L-1。     

碱性藏花红-十二烷基苯磺酸钠-蛋白质体系的荧光反应及其分析应用

阳离子染料碱性藏花红(ST)及其二聚体可平衡转化,形成平衡体系。在适宜浓度的阴离子表面活性剂的存在下,蛋白质的定量加入可调节这一平衡,引起体系荧光有规律的变化。在此基础上,研究了体系的吸收光谱和荧光光谱特性,建立了一种测定蛋白质的方法。实验表明,碱性藏花红在阴离子表面活性剂的作用下,自聚程度增加,体系荧光降低。加入蛋白质体系荧光增强,且增强程度与体系中的蛋白质的加入量呈线性关系。在优化实验条件下,线性范围为0～40 μg·mL-1,检出限为0.034 μg·mL-1。方法简便、快速、准确、灵敏度高,选择性好,用于人血清蛋白的测定,结果令人满意。     

Effect of cationic and anionic surfactants on morphology and luminescent properties of YVO4: Bi,Eu3+ red phosphors

Using cationic surfactant cetyltrimethylammonium bromide (CTAB) and anionic surfactant sodium dodecylbenzene sulfonate (SDBS), respectively, YVO₄: Bi, Eu³⁺ red phosphors were prepared by a facile reaction chemistry method and their morphology, structure and luminescent properties were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and fluorescence spectrometer. The results showed that the introduction of cationic and anionic surfactants not only greatly influenced their morphology, but induced a remarkable change XRD patterns. The reason that causes the variation of these properties for YVO₄: Bi, Eu³⁺ red phosphors was concluded to be related to different surfactants.     

Role of the head group on the mixed micellization process in binary systems containing a sugar-based surfactant: decanoyl- N -methylglucamide

The mixed micelles of nonionic decanoyl-N-methylglucamide (MEGA-10) with the anionic sodium dodecyl sulphate (SDS), the cationic dodecyltrimetylammonium bromide (DTAB), and the nonionic octaoxyethylene monododecyl ether (C₁₂E₈) have been studied using the fluorescence probe technique. The critical micelle concentration of the three mixed systems in the whole composition range were determined by the pyrene 1:3 ratio method, and the experimental results were analysed in the context of the pseudophase separation model, by using the regular solution theory. It was found that the mixed micelles containing the anionic surfactant are more stable than the pure micelles. This fact was attributed to the occurrence of ion–dipole interactions between the head groups of the component surfactants in the mixed micelle. The static quenching method was used to determine the mean aggregation number of pure and mixed micelles. It was found that whereas mixed micelles containing SDS show a positive deviation from the ideal behaviour, those constituted by DTAB deviate negatively. This different tendency was interpreted on the basis of both steric and electrostatic interactions. The evolution of the microstructure of the mixed micelles upon the participation of the co-surfactant was followed through the micropolarity and microviscosity of the mixed systems. Although the micropolarity studies do not allow definite conclusions, the microviscosity assays indicate that the participation of the co-surfactant induces the formation of less ordered micelles, this effect being more pronounced in the case of mixtures with the anionic surfactant.     

Premicellar and micelle formation behavior of aqueous anionic surfactants in the presence of triphenylmethane dyes: protonation of dye in ion pair micelles

The premicellar and micelle formation behaviors of four cationic triphenylmethane dyes, viz, Pararosaniline (RN), Crystal violet (CV), Ethyl violet (EV), and Malachite green (MG), in aqueous anionic surfactant solutions of sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), and sodium dodecyl sulfonate (SDSN) have been studied by spectral and surface tension measurements. The study was carried out within a pH range where the dyes are stable in their quinoid forms. The dyes have been found to form dye–surfactant ion pairs (DSIPs) with the surfactants, at the surfactant concentrations well below their critical micelle concentration, CMC*. The DSIPs behave like nonionic surfactants and form an air–water interfacial monolayer. The DSIPs have a lower critical micelle concentration (CMC_IP), greater efficiency, and lower effectiveness than the corresponding pure surfactants. As the surfactant concentration is increased below the CMC*, the DSIPs start forming micelles of their own where the dye gets protonated and exists as a protonated dye–surfactant ion pair (PDSIP) in the ion pair micelles. As the concentration of the surfactant exceeds the CMC* of the pure surfactant, the protonation reverses gradually with the dye remaining in the micelles in solubilized form and the DSIPs in the air–water interfacial monolayer are replaced by pure surfactants. The distorted helical isomeric form (isomer B) of the dyes is favored in the PDSIPs. Copyright © 2009 John Wiley & Sons, Ltd.     

Study of protein-probe complexation equilibria and protein-surfactant interaction using charge transfer fluorescence probe methyl ester of N,N-dimethylamino naphthyl acrylic acid

In this paper, we demonstrate the interaction between intramolecular charge transfer (ICT) probe—Methyl ester of N,N-dimethylamino naphthyl acrylic acid (MDMANA) with bovine serum albumin (BSA) using absorption and fluorescence emission spectroscopy. The nature of probe protein binding interaction, fluorescence resonance energy transfer from protein to probe and time resolved fluorescence decay measurement predict that the probe molecule binds strongly to the hydrophobic cavity of the protein. Furthermore, the interaction of the anionic surfactant sodium dodecyl sulphate (SDS) with water soluble protein BSA has been investigated using MDMANA as fluorescenece probe. The changes in the spectral characteristics of charge transfer fluorescence probe MDMANA in BSA-SDS environment reflects well the nature of the protein-surfactant binding interaction such as specific binding, non-cooperative binding, cooperative binding and saturation binding.     

Kinetics of Surfactant-induced Aggregation of Lysozyme Studied by Fluorescence Spectroscopy

The study of protein conformational changes in the presence of surfactants and lipids is important in the context of protein folding and misfolding. In the present study, we have investigated the mechanism of the protein conformational change coupled with aggregation leading to size growth of Hen Egg White Lysozyme (HEWL) in the presence of an anionic detergent such as sodium dodecyl sulphate (SDS) in alkaline pH. We have utilized intrinsic protein fluorescence (tryptophan) and extrinsic fluorescent reporters such as 8-anilinonaphthalene-1-sulfonic acid (ANS), dansyl and fluorescein to follow the protein conformational change in real-time. By analyzing the kinetics of fluorescence intensity and anisotropy of multiple fluorescent reporters, we have been able to delineate the mechanism of surfactant-induced aggregation of lysozyme. The kinetic parameters reveal that aggregation proceeds with an initial fast-phase (conformational change) followed by a slow-phase (self-assembly). Our results indicate that SDS, below critical micelle concentration, induces conformational expansion that triggers the aggregation process at a micromolar protein concentration range.     

Effects of charge and structure of surfactants on kinetics of water reactions: the pH-independent hydrolysis of bis (2,4-dinitrophenyl) carbonate

The pH-independent hydrolysis of bis (2,4-dinitrophenyl) carbonate in the presence of aqueous micelles of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, alkyltrimethylammonium chlorides, alkyldimethylbenzylammonium chlorides (alkyl GROUP = cetyl and dodecyl), and polyoxyethylene (9) nonylphenyl ether has been studied spectrophotometrically. Observed rate constants, k_obs, decrease in the following order: alkyldimethylbenzylammonium chlorides> bulk water ≈ alkyltrimethyl- ammonium chlorides> nonionic micelles> anionic micelles. Surfactant-substrate association constants have been determined from the dependence of k_obs on [surfactant]. ¹H NMR study of the solubilization of a model compound, phenyl-2,4-dinitrophenyl carbonate, showed that all surfactant segments are affected by the solubilizate, and that the ester penetrates deeper in micelles of alkyldimethylbenzylammonium chlorides relative to the corresponding alkyltrimethylammonium chlorides. Micellar effects on k_obs are analyzed in terms of “medium” and “electrostatic” effects. The lower microscopic polarity at the reaction site cause rate decrease, whereas electrostatic interactions of the dipolar transition state with the charged interface result in rate decrease by anionic micelles, and rate enhancement by cationic ones.     

Weakly charged lamellar bilayer system: Interplay between thermal undulations and electrostatic repulsion

We study the interplay between thermal undulations and electrostatic interactions for weakly charged surfactant bilayers by measuring the backscattering of light from very dilute lamellar phases of the non-ionic surfactant triethylene glycol monodecyl ether (C₁₀E₃) doped with small amounts of the anionic surfactant sodium dodecyl sulphate (SDS), both with and without added electrolyte. Upon charging, the lamellar phases show a transition from undulation to electrostatic stabilization. Non-lamellar structures develop if the molar mixing ratio exceeds . Deviations from ideal swelling, , where is the lamellar repeating distance and the membrane volume fraction, were detected for all lamellar phases. Salt-free lamellar phases with charge densities below , as well as more highly charged lamellar phases at high ionic strength show a universal logarithmic deviation from ideal swelling that was analyzed using theories for undulation stabilized lamellar phases. Deviations from ideal swelling for electrostatically stabilized lamellar phases were analyzed using theories recently developed for undulations in charged lamellar phases. The fits to the various theories yield a value of for the bending modulus of the C₁₀E₃ bilayers. Received 21 June 1999 and Received in final form 25 August 1999     

Exploration of twisted intramolecular charge transfer fluorescence properties of trans-2-[4-(dimethylamino)styryl]benzothiazole to characterize the protein–surfactant aggregates

The characterization of aggregates of an anionic surfactant, sodium dodecyl sulphate (SDS) with bovine serum albumin (BSA) in various regions of binding isotherm of SDS to BSA with increasing concentration of the former have been done by exploring the twisted intramolecular charge transfer (TICT) fluorescence properties of a probe, trans-2-[4-(dimethylamino)styryl] benzothiazole (DMASBT). The TICT fluorescence, steady-state fluorescence anisotropy and time-resolved fluorescence of DMASBT, and the fluorescence resonance energy transfer (FRET) study reveal the characteristics of the native protein as well as the protein–surfactant aggregates viz., micropolarity, microviscosity, locations of probe, denaturation of protein in various regions of binding isotherm, and also the validation of necklace-bead model. The changes in the polarity and the viscosity of the microenvironment around the probe from one binding region of SDS to other have been reflected in the highly sensitive fluorescence properties of DMASBT. The study of FRET between the DMASBT and the tryptophan residue (Trp) of BSA has identified the locations of the probe molecule in the native protein as well as that in various BSA–SDS aggregates. The energy transfer efficiency decreases, whereas the distance between the DMASBT and the Trp residue increases with increasing concentration of SDS. The significant change in the conformations of protein molecules during the non-cooperative binding region of SDS is evidenced by the fluorescence anisotropic behavior of DMASBT in the same region.