正负离子表面活性剂与高聚物混合双水相体系的相行为及蛋白质的分配

报道了由正负离子表面活性剂与高聚物混合溶液形成的一种可用于蛋白质的分离及分析的新型双水相萃取体系.研究了正负离子表面活性剂(溴化十二烷基三乙铵/十二烷基硫酸钠)分别与葡聚糖和聚乙二醇混合双水相体系的形成规律、相行为及牛血清蛋白和溶菌酶在双水相体系中的分配.通过在高聚物分子中接上亲和配基,研究蛋白质在双水相体系中的亲和分配.结果表明,在该体系中,表面活性剂与高聚物分别富集于不同相中.升高温度及加入无机盐均可促进双水相体系的形成,不同蛋白质可分配于不同的相中.亲和配基的引入极大地增强了蛋白质分配的选择性.     

DTAB-月桂酸钠体系表面活性剂双水相研究

绘制和分析了十二烷基三甲基溴化铵（DTAB） 月桂酸钠（SL）组成的表面活性剂混合体系相图,系统研究了温度和无机盐等因素对该体系表面活性剂双水相 (ASTP) 影响的规律性.结果表明:与富含负离子表面活性剂双水相 (ASTP A) 相比较,富含正离子表面活性剂双水相(ASTP C)区域更大、更稳定;温度升高,无机盐(NaBr)的浓度增大,都引起 ASTP 体系上相体积的减小和下相体积的增加;囊泡普遍存在于ASTP的上下相之中.     

十四烷基三甲基氯化铵/十二烷基苯磺酸钠混合表面活性剂双水相体系的萃取性能

研究了十四烷基三甲基氯化铵(TTAC)与十二烷基苯磺酸钠(SDBS)混合表面活性剂水溶液双水相体系的分相情况、萃取性能及两相的微观结构.结果表明,TTAC/SDBS混合表面活性剂水溶液在30℃下能够形成稳定的双水相体系;该双水相体系对亚甲基蓝、靛红都具有一定的萃取分离作用.其上、下两相的微观结构明显不同,这是其能够形成稳定双水相体系且具有萃取作用的重要原因.     

表面活性剂双水相的性质及其应用 Ⅰ. 表面活性剂双水相的微环境性质

阴、阳离子表面活性剂混合体系，在一定浓度及混合比范围内，可以形成两个互不相溶、平衡共存的水相，称为表面活性剂双水相．其中阳离子表面活性剂过量的双水相体系，称为阳离子双水相．本文分别以芘和罗丹明B作为探针，用荧光探针法研究了摩尔比为1：6：1的C_12NE和SDS混合体系所形成的阳离子双水相，测定其上层和下层的胶束微环境的极性和微粘度，取得了有意义的结果．     

表面活性剂双水相界面性质的研究

表面活性剂双水相是指正、负离子表面活性剂混合水溶液在一定浓度及混合比 范围内，自发分离形成的两个互不相溶的水相。前文报道了将其作为一种新型萃取 体系，用于生物活性物质的分离。目前有关其相行为、化学物质和生物大分子的分 配方面已有较多研究，但未见两相之间界面化学性质研究的报道。表面活性剂双水 相的形成是一种奇特的相分离现象，两个稀水溶液（含水量可高达99%以上）互不 相溶、平衡共存，其界面结构和界面张力必有其特殊性。     

蛋白质在表面活性剂与高分子共组双水相体系中 的分配

高分子和正负离子表面活性剂混合物可形成一种新型双水相体系。研究蛋白质在溴化十二烷基三乙铵/十二烷基硫酸钠与聚氧乙烯(EO)-聚氧丙烯(PO)嵌段共聚物(EO~2~0PO~8~0)共组双水相体系中的分配。通过在高分子接上亲和配基,研究蛋白质在带有亲和配基高分子的双水相体系中的分配。将表面活性剂富集相稀释或加热高分子富集相,又可形成新的双水相体系,由此可进行蛋白质的多步分配。在蛋白质的分配完成之后,通过将表面活性剂富集相进一步稀释或将高分子富集相加热至高分子浊点以上可将表面活性剂和高分子与目标蛋白质分离。正负离子表面活性剂和高分子还可以循环使用。     

正离子型疏水改性聚氧乙烯单成相组分双水相系统的相行为

对正离子型疏水改性聚氧乙烯(HM-EO)单成相组分双水相系统的相行为进行了考察,并分析其电荷特性.HM-EO在水溶液中呈现两亲性,可以形成胶束,进而形成带电的胶束簇集体.通过改变溶液的pH值、盐浓度及添加带相反电荷的表面活性剂SDS,可改变胶束簇集体的带电状态,从而影响系统的相行为.增大pH值,有利于系统的分相.盐的添加也可以增大双水相两相区域,正离子影响次序为K+>Na+,负离子次序为SO42->F->Cl->Br->I-.进一步考察了HM-EO和SDS之间的相互作用,结果表明SDS能与HM-EO形成混合胶束簇集体,改变HM-EO双水相系统的带电特性.     

表面活性剂双水相的性质及其应用 Ⅰ. 表面活性剂双水相的微环境性质

阴、阳离子表面活性剂混合体系, 在一定浓度及混合比范围内, 可以形成两个互不相溶、平衡共存的水相, 称为表面活性剂双水相。其中阳离子表面活性剂过量的双水相体系, 称为阳离子双水相。本文分别以芘和罗丹明B作为探针, 用荧光探针法研究了摩尔比为1.6:1的C12NE和SDS混合体系成形成的阳离子双水相,测定其上层和下层的胶束微环境的极性和微粘度, 取得了有意义的结果。     

正负离子表面活性剂/离子液体双水相性质研究

本文把短链离子液体(IL)四氟硼酸1-乙基-3-甲基咪唑鎓[C2mim]BF4引入正负离子表面活性剂十二烷基硫酸钠(SDS)和十二烷基三甲基溴化铵(DTAB)双水相体系(SDS/DTAB/H2O)中,研究了IL对双水相相图及相分离体系性质的影响。结果表明,[C2mim]BF4的阳离子性质是影响阴离子表面活性剂过量区域性质的主要因素,IL通过静电作用、氢键作用等改变体系中聚集体的形貌,最终导致阴离子双水相(ATPSa)的消失。IL的阴离子对阳离子双水相(ATPSc)区域性质起着决定作用;IL的盐效应引起的对表面活性剂混合胶束扩散双电层的压缩作用,不但促进胶团的形成,缩短了形成稳定胶团所需要的时间,加快了双水相的相分离速度,而且也造成了形成ATPSc所需DTAB含量的提高。IL的引入改变了ATPSc上、下相表面活性剂的组成及含量,使富含表面活性剂的上相中阳离子表面活性剂含量更高,进而提高了双水相的萃取性能,其上相对甲基橙的萃取效率可高达96.67%。     

环境因素对正负表面活性剂体系相行为的影响

在1:1正负离子表面活性剂混合体系(十二烷基硫酸钠/辛基三甲基溴化铵 SDS-C8NM3Br; 十二烷基硫酸钠/十二烷基三甲基溴化铵,SDS-C12NM3Br)中加入短链脂肪醇 (乙醇,正丙醇,正丁醇),正负离子表面活性剂沉淀溶解,出现表面活性剂双水相.上相有液晶存在,下相有囊泡自发形成.折光率数据和电镜结果表明:上相为表面活性剂富集相,下相表面活性剂浓度较低.混合体系中,出现表面活性剂双水相所需短链脂肪醇的体积百分数,随短链脂肪醇的链长增加而降低.温度升高,出现表面活性剂双水相所需短链脂肪醇的体积百分数降低.对SDS/C8NM3Br/H2O体系的研究结果表明:超声处理,可使混合体系中沉淀向囊泡转化,与短链脂肪醇的加入后的作用类似.     

SDS/CTAB/H2O的双水相性质及萃取作用

正负离子表面活性混合物;牛血清蛋白质;色氨酸;SDS/CTAB/H2O的双水相性质及萃取作用     

Rheology and microstructure studies of SDS/CTAB/H2O system

Phase behavior of mixed sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB) aqueous solution was studied. The rheological properties and microstructure were investigated using a rheostat and freeze-fracture technique and are shown to be closely related to the phase behavior. Experimental investigations reveal two symmetrical aqueous two-phase systems (ATPS) in the ternary phase diagram of SDS/CTAB/H₂O system. In the surfactant rich phase of ATPS or in the adjacent stoichiometric state of ATPS, the system has high viscosity because of its long range ordered structure. Lamellar phase was found in the high viscosity samples in which the cationic and anionic surfactant are in 1: 3 or 3: 1 stoichiometry. In addition, the viscosity has a tendency to increase when salt was added to the solution. The viscosity increase is due to the salt can screen the repulsion between different charged headgroups and thus reduces the effective size of surfactants and facilitates the spherical or rod likes micelles to be transformed to worm-like micelles which can form hexagonal or liquid crystal phases. Large-size salt ions like sodium sulfate (especially organic salt ions) have more significant effect on the surfactant solution viscosity. The text was submitted by the authors in English.     

Salt Effects on Aqueous Cationic/Anionic Surfactant Two‐Phase Regions

The influence of added salts (KCl, NaF, NaCl, NaBr, Na₂SO₄, Na₃PO₄) on aqueous cetyltrimethylammonium bromide (CTAB)/sodium dodecyl sulfonate (AS) two‐phase regions were studied. For KCl, the concentration dependence of salt effect on aqueous two‐phase regions was investigated. When brine substitutes pure water as a solvent, the positions of aqueous two‐phase regions in the phase diagram change. The results indicate that for aqueous two‐phase systems with excess anionic surfactant (ATPS‐A), the salt effect was mainly dependent on the cationic inorganic counterions, whereas for aqueous two‐phase systems with excess cationic surfactant (ATPS‐C), the salt effect was mainly dependent on the anionic inorganic counterions. The shift of aqueous two‐phase region is strengthened following the Hofmeister series. All the experiments were performed at 318.15 K.     

Effect of salt additives on partition of nonionic solutes in aqueous PEG-sodium sulfate two-phase system

Partition of 12 nonionic organic compounds in aqueous PEG-8000-Na(2)SO(4) two-phase system was examined. Effects of four salt additives (NaCl, NaSCN, NaClO(4), and NaH(2)PO(4)) in the concentration range from 0.027 up to ca. 1.9 M on binodal curve of PEG-sulfate two-phase system and solute partitioning were explored. It was found that different salt additives at the relatively high concentrations display different effects on both phase separation and partition of various nonionic solutes. Analysis of the results indicates that the PEG-Na(2)SO(4) ATPS with the up to 0.215 M NaCl concentration may be viewed as similar to the ATPS without NaCl in terms of the Collander equation's predictive ability of the partitioning behavior of nonionic compounds. All ATPS with each of the salt additive used at the concentration of 0.027 M may be viewed as similar to each other as the Collander equation holds for partition coefficients of nonionic solutes in these ATPS. Collander equation is valid also for the compounds examined in the ATPS with additives of NaSCN and NaClO(4) at the concentrations up to 0.215 M. The observed similarity between these ATPS might be explained by the similar effects of these two salts on the water structure. At concentrations of the salt additives exceeding the aforementioned values, different effects of salt additives on partitioning of various nonionic solutes are displayed. In order to explain these effects of salt additives it is necessary to examine the intensities of different solute-solvent interactions in these ATPS within the framework of the so-called Linear Solvation Energy Relationship (LSER) model.     

离子液体在多水相液液平衡体系中的作用

通过用短链离子液体(1-乙基-3-甲基咪唑溴盐[C2mim]Br、1-丁基-3-甲基咪唑溴盐[C4mim]Br)部分或全部取代SDS/DTAB/PEG/NaBr/H2O多水相体系中的无机盐NaBr,用长链离子液体十二烷基-3-甲基咪唑溴盐[C12mim]Br部分取代体系中阳离子表面活性剂DTAB,系统研究了离子液体在分相体系中的作用及其对分相体系性质的影响.研究表明,SDS/DTAB/PEG/NaBr/H2O混合体系形成的四水相体系可以看作"聚合物双水相"与"表面活性剂双水相"共存的结果.短链离子液体([C2mim]Br、[C4mim]Br)较强的亲水性能赋予其较强的盐析能力,在混合体系中表现出明显的盐效应,保证了四水相体系中"聚合物双水相"的存在.短链离子液体与聚合物之间的相互作用及其对表面活性剂之间相互作用的影响均不可忽略.对混合体系的相行为,共存多相的性质有重要的影响.而长链离子液体[C12mim]Br主要通过自身的疏水作用影响"表面活性剂双水相"的性质,充当表面活性剂的角色.然而,[C12mim]Br与DTAB分子结构上的差异,导致表面活性剂分子在"表面活性剂双水相"的两相重新分配,影响了对应两相的体积及萃取能力.可见,通过调节离子液体的烷基链长、混合体系中的含量等可获得具有特定性质的多水相体系.     

离子液体双水相体系萃取分离牛血清白蛋白

建立了由亲水性离子液体四氟硼酸1-甲基-3-丁基咪唑([Bmim]BF4)和KH2PO4形成的双水相体系萃取分离牛血清白蛋白(BSA)的新方法。研究了不同盐及盐的浓度、离子液体浓度以及蛋白质用量、溶液酸度、其它共存物质对双水相成相及BSA萃取率的影响,结果表明,磷酸二氢钾盐浓度为80g/L,离子液体浓度在160~240mL/L,BSA的浓度为30~50mg/L,溶液酸度在pH4~8范围,离子液体双水相体系对BSA有较高的萃取率。用加入不同类型表面活性剂探讨了离子液体与蛋白质之间的作用。     

Salt Effects on the Aqueous Two-Phase System of Gemini(12-3-12, 2Br<Superscript>−</Superscript>)/SDS/PEG

The effect of added salts (NaCl, KCl and NaBr) on the aqueous two-phase system (ATPS) formed in mixtures of Gemini(12-3-12, 2Br⁻)/sodium dodecyl sulfate/polyethylene glycol has been investigated. Phase diagrams of the aqueous systems containing Gemini(12-3-12, 2Br⁻), sodium dodecyl sulfate (SDS), polyethylene glycol(PEG) and a salt have been determined experimentally at 313.15 K. The results indicate that the addition of salts not only induces the appearance of ATPS-A (in which anionic surfactant is in excess), shortens the phase separation time, enlarges the regions of ATPS-C (in which cationic surfactant is in excess), and decreases the minimum concentration required for forming an ATPS, but also alters the matching between anionic and cationic surfactants. Extractive experiments also showed that these salts notably enhance the extraction ability of ATPS; the Gemini-rich phase exhibits prominent cohesive action with xylenol orange, regardless of whether or not it is the upper phase or the lower phase.     

Modeling of liquid–liquid equilibrium of polyethylene glycol-salt aqueous two-phase systems—the effect of partial dissociation of the salt

The modified NRTL model proposed in the previous paper [Y.-T., Wu, D.-Q. Lin, Z.-Q. Zhu, L.-H. Mei, Fluid Phase Equilibria 124 (1996) 67–79.] is further extended to include the effect of partial dissociation of salts in polyethylene glycol (PEG)–salt aqueous two-phase systems (ATPS), and is used to calculate the liquid–liquid equilibrium phase diagrams such as PEG–(NH₄)₂SO₄ and PEG–MgSO₄ ATPS. The phase diagrams of PEG–uni-bivalent salt ATPS can be correctly represented in the cases of both complete dissociation and partial dissociation of the salt, while those of PEG–MgSO₄ ATPS can only be described in the case of partial dissociation of the salt. The analysis shows that the salts may have different existing states in the ATPS. The effect of partial dissociation of the salts on the phase diagrams should be considered, especially for systems such as PEG–MgSO₄ ATPS.     

pH及有机小分子物质对SDS/CTAB/H2O系统双水相性质的影响

正离子表面活性剂与负离子表面活性剂混合物能产生比单一表面活性剂更高的表面活性[1 ] 。在适当条件下 ,正负离子表面活性剂的水溶液能产生两个互不相溶的水相 ,即表面活性剂双水相系统[2 ] (ＡｑｕｅｏｕｓＴｗｏ -ＰｈａｓｅＳｙｓｔｅｍ -ＡＴＰＳ)。作者曾指出双水相上相为液晶 (ＬｉｑｕｉｄＣｒｙｓｔａｌ -ＬＣ)结构 ,下相为各向同性溶液 ,盐离子通过改变双水相中表面活性剂有序组合体的反离子层的状态而对双水相的组成、结构等产生重要的影响[3,4] 。本文进一步研究ｐＨ及有机小分子物质在十二烷基硫酸钠 /十六烷基三甲基溴化铵 /…     

Nitroprusside-PEO enthalpic interaction as a driving force for partitioning of the [Fe(CN)(5)NO](2-) anion in aqueous two-phase systems formed by poly(ethylene oxide) and sulfate salts

Ions are known to concentrate in the salt-enriched phase of aqueous two-phase systems, with the only known exception being the pertechnetate anion, TcO(4)(-). We have discovered a second ion, nitroprusside anion (NP), which is markedly transferred from the salt phase to the polymer phase. The partitioning behavior of [Fe(CN)(5)NO](2-) anion was investigated in ATPS formed by poly(ethylene oxide) of molar mass 3350 and 35000 g mol(-1), and different sulfate salts (Na(2)SO(4), Li(2)SO(4), and MgSO(4)). On the basis of a model, the nitroprusside high affinity for the macromolecular phase was attributed to an enthalpic specific interaction between the anion and ethylene oxide unit. Partition coefficients increased exponentially with tie-line length increase, reaching values as high as 1000 and showing a relationship very dependent on the salt nature, but independent of the polymer molar mass.