浊点萃取技术及其应用研究进展

浊点萃取是近年来发展起来的一种样品前处理技术。本文介绍了浊点萃取方法的相分离行为,讨论了关键因素如表面活性剂结构和浓度、平衡温度与时间、添加剂等对萃取效率的影响,总结了操作方法和优化。文章结合近年来的研究成果,对浊点萃取技术在金属离子、蛋白质和有机污染物分离富集中的应用进行了评述。最后探讨了浊点萃取技术的发展前景。     

苯酚在浊点萃取中凝聚层相的增溶规律

采用分光光度法测定了苯酚在非离子表面活性剂单相胶束溶液中和在非离子表面活性剂两相浊点萃取时凝聚层相中的增溶结果.实验表明：溶质在凝聚层相的增溶与表面活性剂形成胶束的结构有关.当凝聚层相的表面活性剂形成正相胶束时,溶质在凝聚层相的增溶规律和在表面活性剂胶束溶液中的增溶规律一致;当凝聚层相的表面活性剂形成反相胶束时,溶质在凝聚层相和在溶液相的浓度关系可理解为在这两种溶剂之间的分配随着凝聚层相的含水率逐渐降低趋近于一定值,溶质的分配系数也趋近于一定值.     

浊点萃取—火焰原子吸收光谱法测定痕量镉

以1-（2-吡啶偶氮）-2-萘酚（PAN）为络合剂、以Triton X—100为表面活性剂进行浊点萃取建立了浊点萃取——火焰原子吸收光谱法测定痕量镉的方法。探讨了络合剂的浓度、溶液的pH,缓冲溶液的浓度、表面活性剂的浓度等影响浊点萃取的因素。该方法用于自来水、湖水、雨水中痕量镉的测定,具有低毒,高效,安全,简便等特点。     

聚醚型非离子表面活性剂的浊点及其影响因素

总结了非离子表面活性剂浓度、外加聚合物、离子表面活性剂、无机电解质、助表面活性剂等对聚醚型非离子表面活性剂水溶液浊点的影响规律 ,发现聚合物由于其结构和分子量不同对浊点的影响也不同 ,一般可使浊点降低 ;加入离子表面活性剂可以和非离子表面活性剂形成混合胶束 ,从而使浊点升高 ;无机盐由于存在盐析和盐溶两种不同效应而对浊点的影响比较复杂 ;醇和有机酸等助表面活性剂根据其碳链的长短不同而影响浊点。这些规律对非离子表面活性剂的研究和应用有一定的指导意义。     

浊点萃取-火焰原子吸收光谱法测定水样中的微量钴

文章研究了浊点萃取-火焰原子吸收光谱法测定微量钴。以8-羟基喹啉（8-HQ）作为钴的络合剂,以Triton X-100为表面活性剂进行浊点萃取。探讨了影响浊点萃取的因素,如溶液的pH,络合剂的浓度,表面括性剂的浓度,缓冲溶液的浓度,加入表面活性剂后的平衡温度和时间。该方法具有低毒,高效,安全,简便等特点,并用于自来水、湖水、江水、雨水中微量钴的溯定,其富集率最高可达100％,回收率在90％～100％之间,方法可行。     

非离子表面活性剂TX114浊点萃取D2EHPA的规律

引言浊点萃取[1-2]是利用表面活性剂水溶液的增溶和分相行为实现溶质富集的分离技术。由于分相后表面活性剂的富集相(亦称凝聚相)与水相的体积比非常小(0.007～0.04)[3],所以,对于被增溶的物质能够提供非常高的富集倍数和萃取效率。目前浊点萃取技术主要广泛应用于痕量有害物质     

浊点萃取-高效液相色谱法测定某些中草药中铜的研究

基于浊点现象,建立了以双硫腙为配位剂、TritonX-114为表面活性剂的浊点萃取-高效液相色谱法测定中草药中痕量铜的新方法。研究了溶液pH值、配位剂的浓度、表面活性剂的浓度、平衡温度和平衡时间、流动相类型等实验条件对浊点萃取及铜测定的影响。在最佳试验条件下,该方法的线性范围为0．1—120μg·L^-1,相关系数达0．997-0．999,铜的检出限达到0．1μg·L^-1。相对于传统的液相色谱分析法灵敏度提高了18倍。该方法成功用于中草药样品中铜的测定并获得了满意的结果。     

表面活性剂在植物活性成分提取中的应用

综述了表面活性剂在植物活性成分提取中的应用。主要介绍了表面活性剂在辅助提取、微乳体系提取、浊点萃取植物活性成分中的应用及其作用原理和特点,并对表面活性剂在提取植物活性成分中的应用前景进行了展望。     

论述浊点萃取在环境化学方面的应用

文章首先分析了表面活性剂应用在浊点萃取中的作用,并对环境化学做出具体的研究,帮助读者明确提升萃取反应速率的有效方法。其次重点探讨温度变化促进萃取反应进行的原理,并对浊点萃取中需要优化的内容进行重点分析,帮助提升浊点萃取反应的稳定性,解决排放污染问题。     

浊点萃取技术及其在农药残留分析中的应用

浊点萃取技术是基于表面活性剂溶液相分离现象的一种新兴的液-液萃取技术,已经成功的与多种分析仪器联用,用于农药残留样品的前处理中。介绍了浊点萃取技术的原理和影响因素,重点综述了浊点萃取作为气相色谱、液相色谱、分光光度计、荧光光度计的前处理技术在农药残留分析中的应用进展,探讨了该技术方法的发展前景。     

Nonionic surfactants induced cloud point extraction of Polyhydroxyalkanoate from Cupriavidus necator

Polyhydroxyalkanoate synthesized by Cupriavidus necator DSM 428 was purified from the crude fermentation broth as such by performing nonionic surfactants (Triton X100, Triton X114 & Tergitol 6) induced cloud point extraction. Polyhydroxyalkanoate was extracted into the micelle-rich bottom phase (coacervate phase), while most of the cellular impurities partitioned into the aqueous phase. Cloud point temperatures and the extraction efficiency of different cloud point systems were studied at different pH value and in the presence of additives. Maximum extraction of biopolymer was achieved (recovery of 84.4%) with a purity of 92.49% at 3 pH with the addition of 0.1 M ammonium chloride in the mixed surfactant system at a reduced cloud point temperature of 33°C.     

非离子型表面活性剂的双水相性质及萃取作用

引　言双水相萃取技术是近年来发展很快的一种生物分离方法[1,2 ] .由于系统中分层的两相都是水相 ,所以该系统为物质的分离特别是生物活性物质的分离提供了温和的环境 .在免疫分析、生物转化等方面也具有良好的应用前景[3] .以往对双水相系统的开发利用基本上仅局限于高分子系     

Microemulsion Extraction of Monascus Pigments from Nonionic Surfactant using High Polarity of Diethyl Ether as Excess Oil Phase

Stripping of organic compound from nonionic surfactant micelle aqueous solution is indispensable for many industrial processes. In this paper, a relatively high polarity diethyl ether was screened for forming Winsor I microemulsion, which was used for stripping of organic compound from nonionic surfactant. Setting up extractive fermentation of Monascus pigments in Triton X-100 aqueous solution as a model, cloud point extraction of Monascus pigments from fermentation broth, and back-extraction of Monascus pigments from the coacervate phase of cloud point system by Winsor I microemulsion were conducted. Monascus pigments were successfully separated from nonionic surfactant into the excess diethyl ether phase.     

Extraction of Parabens from Water Samples Using Cloud Point Extraction with a Non-Ionic Surfactant with β-Cyclodextrin as Modifier

A cloud point extraction process using a silicone non-ionic surfactant to extract selected parabens compounds from water samples was investigated using reversed phase high performance liquid chromatography. The cloud point extraction process, in the presence of β-cyclodextrin (β-CD) as a modifier, is a new extraction process which was optimized with five parameters, i.e. salt concentration, pH of the solution, temperature, surfactant concentration and β-CD concentration. The developed method with the β-CD modifier results in an excellent performance on detection of parabens from water samples with limits of detection in the range of 0.017–0.043 μg/L and percentage recoveries from 90.5 to 98.9 %.     

Temperature‐induced surfactant‐ mediated pre‐concentration of uranium assisted by complexation

Cloud‐point extraction (CPE) was used with lipophilic chelating agent to extract uranium(VI) from aqueous solutions. The methodology used is based on the formation of metal complexes soluble in a micellar phase of a non‐ionic surfactant, Triton X‐114. The metal ions complexes are then extracted into the surfactant‐rich phase at a temperature above the cloud‐point temperature. The influence of surfactant concentration on extraction efficiency was studied and the advantage of adding 8‐hydroxyquinoline (8HQ) as lipophilic chelating agent was evidenced. High extraction efficiency was observed, indicating the feasibility of extracting U(VI) using CPE. This study describes a four‐step process—(1) extraction, (2) thermo‐induced phase splitting, (3) back‐extraction and (4) second phase splitting—for the recovery of uranium from water. In our conditions, the extraction yield is quantitative and the concentration factor obtained is superior to 100. After stripping with a diluted nitric acid solution (pH < 1), the system can be recycled through a new four‐step cycle. Copyright © 2006 Society of Chemical Industry     

Cloud Point Extraction of Four Triphenylmethane Dyes by Triton X-114 as Nonionic Surfactant

A method for removing four triphenylmethane dyes from wastewater by cloud point extraction with the nonionic surfactant Triton X-114 (TX-114) was developed. The triphenylmethane dyes were crystal violet, ethyl violet, malachite green and brilliant green. The cloud point of TX-114 generally increased in the presence of any of the four dyes. In the cloud point system, these dyes were solubilized into a coacervate phase that left a color-free dilute phase. The extraction efficiency of the dyes increased with the temperature, TX-114 concentration, and salt (NaCl and CaCl₂) concentration. More than 97% TX-114 in the dilute phase was recovered by adjusting the volume ratio of dichloromethane to the dilute phase. The Langmuir-type adsorption isotherm was used to describe the dye solubilization. The Langmuir constants m and n were calculated as functions of temperature. The results showed that the solubilization of the triphenylmethane dyes in the cloud point system was related to the partition coefficient and their molecular structures.     

Aqueous Surfactant Two‐Phase Systems for the Continuous Countercurrent Cloud Point Extraction

Aqueous nonionic surfactant solutions split into two phases if the temperature is increased beyond a certain temperature, the so‐called cloud point temperature. Presently many different types of nonionic surfactants are produced commercially, out of these numerous have been considered as potential solvent for the cloud point extraction. In this work the crucial thermophysical properties of nonionic surfactants are investigated to determine the potential of surfactant systems for extraction processes. Phase equilibria of the binary system Triton X‐114/water and the ternary system Triton X‐114/water/phenol were measured. Based on these data the cloud point extraction was implemented in a continuous stirred extraction column. It was found, that increasing temperature within the column reduces the loss of surfactant and leads to an increasing enrichment factor. This work demonstrates that surfactant/water systems represent a suitable alternative to conventional solvents and can effectively be processed in continuous extraction columns.     

浊点萃取-紫外可见光谱法测定痕量钴

研究了浊点萃取(CPE)-紫外可见光谱法(UV/Vis)测定微量钴的新方法,利用表面活性剂聚乙二醇辛基苯基醚(TritonX-100)和配合剂2[(5-溴-2-吡啶)-偶氮]-5-(二乙氨基)苯酚(5Br-PADAP)对试样中的钴(Ⅱ)进行浊点萃取。探讨了影响浊点萃取及测定灵敏度的因素。在最佳条件下,钴的富集倍率为5,检出限为1.18ng/mL(n=11),RSD为2.8%(n=5,c(Co2+)=0.20μg/mL),钴含量在(0.01～0.5)μg/mL范围内服从比尔定律。本法对实际样品中的钴进行富集和测定,结果令人满意。     

Partitioning equilibria in multicomponent surfactant systems for design of surfactant-based extraction processes

Aqueous biphasic systems based on nonionic surfactants have perspective applications in extraction processes, in particular, cloud point extraction of hazardous compounds or high valued products, especially biomolecules. Additives (e.g., ionic surfactants, salts) and variations in pH can significantly affect the surfactant-based separation processes, representing an additional degree of freedom for their optimization. However, there are few systematic studies of phase and partition behavior for these multicomponent surfactant systems.In this study we examined the clouding, phase compositions and partitioning equilibria for aqueous mixed surfactant systems of a nonionic surfactant (Triton X-114), ionic surfactants (cetyltrimethylammonium bromide or sodium dodecyl sulfate) and NaCl, in order to improve the extraction efficiency. Vanillin was used as a model substance at three different pH values, specifically in (partly) dissociated or non-dissociated states. The partition coefficients obtained in the batch experiments were compared to the predictions by the thermodynamic model COSMO-RS. Based on this knowledge a continuous multistep extraction process was carried out.To the best of our knowledge this is the first demonstration of using a mixed surfactant system for continuous countercurrent cloud point extraction.     

有机硅表面活性剂对水体中多环芳烃的浊点萃取研究

Cloud point extraction （CPE） processes with two silicone surfactants, Dow Coming DC-190 and DC-193, were studied as preconcentration and treatment for the water polluted by three trace polycyclic aromatic hydrocarbons （PAHs）： anthracene, phenanthrene and pyrene. For all cases, the volumes of surfactant-rich phase obtained by two silicone surfactants were very small, i.e. a lower water content in the surfactant-rich phase was obtained. For example, less than 3% of the initial solution was obtained in a 1% （by mass） surfactant solution, which was much smaller than that of TX-114 in the same surfactant concentration. And TX-114 is known as a high compact surfactant-rich phase among most nonionic surfactants, thus the comparison showed that an excellent enrichment was ensured in the analysis application by the CPE process with the silicone surfactants, and the lower water content obtained in the surfactant-rich phase is also important in the large scale water treatment. The influences of additives and phase separation methodology on the recovery of PAHs were discussed. Comparing with DC-193, DC-190 has a lower cloud point and a higher recovery （near 100%） of all the three PAHs in same surfactant concentration, which was required for application as a preconcentration process prior to HPLC system. However the DC-190 solution is hard to be phase separated only by heating, whereas DC-193 has a relative higher phase separating speed by heating, but a high cloud point （around 360K） limits its application. Due to the phase separation by heating is the only method of CPE suitable to the large scale water treatment, the mixtures of two silicone surfacrants solutions were investigated in this study. A solution containing 1% of mixed DC-190 and DC-193 （in the ratio of 90 ： 10） removed anthracene, phenanthrene and pyrene near 100% with a relative low cloud point and quick phase separating speed.