硫酸铯/聚乙二醇双水相体系在298.15K的相平衡

水溶性高聚物的双水相体系可用于纯化一些无机盐,获得高纯晶体。由于高聚物的存在会减小盐在溶液中的溶解度,从而可能析出晶体。本文采用自制的相平衡装置,测定了硫酸铯／聚乙二醇(PEG1000,4000,10000)双水相体系在298．15K时的等温平衡溶解度。     

PEG-无机盐双水相体系萃取水榆花楸叶中总黄酮

水榆花楸叶中所含的黄酮类化合物具有一定的药用价值,利用双水相技术萃取水榆花楸叶中的黄酮是一种有效的分离纯化方法。本文考察了不同种类的无机盐与不同相对分子量的PEG组成的双水相体系的两相性质,研究了PEG1000-Na_2SO_4双水相体系中分离纯化水榆花楸黄酮时PEG的质量分数、Na_2SO_4的质量分数、温度、p H、KCl添加量这5个因素对分配行为的影响,并通过正交实验优化了试验条件。结果表明最佳双水相萃取条件为:Na_2SO_4的质量分数为15%,PEG1000质量分数为30%,p H为9,提取温度为25℃,KCl的添加量为3%,此时原料中黄酮的萃取率可高达97.01%。因此,该体系是一种高效分离纯化水榆花楸叶中黄酮的方法。     

双水相萃取结合液相色谱法分离蛋白质

建立了PEG/( NH4)2SO4双水相体系萃取富集,结合液相色谱分离分析多种蛋白质的方法.考察了无机盐种类和浓度、PEG分子量、pH值和温度等因素对双水相形成以及对细胞色素C、肌红蛋白、牛血清白蛋白、溶菌酶、胰蛋白酶分配行为的影响.结果表明,上述5种蛋白在室温、pH 3.5～9.0范围内,可在15％ PEG-4000/10％ (NH4)2SO4双水相体系中得到富集,且主要集中在下相.同样条件下,血清中的高丰度蛋白在上下相均有分配,下相分配量较大.通过双水相萃取分离蛋白质及对液相色谱一定时间段的色谱峰收集,可初步实现血清中高丰度蛋白质的分离去除.     

聚合物-有机盐双水相体系电促分相研究

本文以PEG-柠檬酸钠双水相体系为研究对象,研究了外加电场对聚合物-有机盐双水相体系分相速率的影响。结果显示增加电场可使聚合物-有机盐双水相体系分相速率提高1~3倍。进而考察了外加电场方向、双水相体系的系线长度(TLL)、相比(VR)、PEG分子量对双水相体系分相速率和电促分相效率的影响。结果表明,电场方向对电促分相效率影响不大;系线长度对分相速率无明显规律性影响,而对电促分相效率影响较大,TLL=40时电促分相效率最高;随着双水相体系相比或成相组分PEG分子量的增加,双水相体系分相速率增大,而电促分相效率降低。     

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.     

聚乙二醇双水相萃取光度法测定镍

用水溶性高聚物、表面活性剂及有机物与无机盐形成的双水相体系萃取分离色素、蛋白质及测定金属离子已有报道[1-5].     

双水相萃取法从风干香肠中分离提取蛋白酶

双水相萃取(ATPS)是近年来发展起来的蛋白纯化方法。为了扩展该方法适应领域,同时为风干香肠形成过程酶系的研究提供具体方法。本实验研究了运用双水相技术分离提取风干香肠中蛋白酶,对构成双水相体系中的PEG分子量、浓度和类型以及盐浓度的影响进行了分析。确定了双水相组成体系为20%PEG1000(m/m)和25%MgSO4(m/m),在此体系中风干香肠的蛋白酶主要分布在上相,最高酶活12.37U/μg;纯化倍数为4.61;回收率为85%。通过分子筛层析对比,表明风干香肠经过双水相分离提取杂蛋白峰被除去,而蛋白酶峰几乎未受到影响,说明该双水相体系萃取香肠中蛋白酶具有良好的专一性。调解双水相pH值对蛋白酶的萃取没有影响,而添加电解质NaCl反而产生不利影响。     

聚丙烯酰胺-聚乙二醇-水体系相图及丙烯酰胺单体在两相中的分配

聚丙烯酰胺(PAAm)和聚乙二醇(PEG)两种水溶液混合时能形成双水相体系,其中上层为PEG富集相,下层为PAAm和PEG的混合相.用凝胶渗透色谱(GPC)法和浊度滴定法研究了PAAm-PEG-H₂O双水相体系的相图,结果表明,随着PEG分子量的升高,体系的分相浓度下降.在PAAm-PEG20000-H₂O体系中,随着体系温度升高,分相浓度先下降后升高,55℃时分相浓度最低.丙烯酰胺(AAm)单体能在两相中发生相分配,分配系数随着PAAm浓度和平衡温度的增加而增大,随着PEG浓度的增加而下降.     

组合表面活性剂-盐-水双水相体系萃取水杨酸和洛美沙星

通过实验选择聚乙二醇(PEG1500)与聚乙烯吡咯烷酮(PVP30000)组合表面活性剂(NH4)2SO4-H2O形成双水相体系及其成相条件。研究水杨酸(APC)和洛美沙星(LFXC)氢键型药物在该双水相体系中的分配行为。结果表明：该体系对APC和LFXC的萃取率分别为102％和69．0％。通过药物在该体系中的紫外吸收光谱及分子荧光光谱的变化,验证其萃取药物的机理。     

聚乙二醇-盐双水相系统萃取头孢呋辛酯的研究

采用聚乙二醇(PEG)-无机盐双水相体系,从药物水溶液中萃取头孢呋辛酯。同时考察PEG分子量及其浓度、不同盐类及其浓度、体系酸碱度、萃取温度对头孢呋辛酯萃取率的影响。结果显示,用PEG-无机盐双水相作为萃取体系的最佳条件为:PEG4000质量分数为19%,NaH2PO4质量分数为28%,pH7.0,温度25℃,一次萃取率约为83.2%。在最佳萃取条件下,进行环境水样加标回收实验,二次萃取率可达92%以上。萃取过程重现性较好,快速、高效且未出现乳化现象。     

Raman spectroscopic study of crystallization from solutions containing MgSO4 and Na2SO4: Raman spectra of double salts

Mg(2+), Na(+), and SO(4)(2-) are common ions in natural systems, and they are usually found in water bodies. Precipitation processes have great importance in environmental studies because they may be part of complex natural cycles; natural formation of atmospheric particulate matter is just one case. In this work, Na(2)Mg(SO(4))(2)·5H(2)O (konyaite), Na(6)Mg(SO(4))(4) (vanthoffite), and Na(12)Mg(7)(SO(4))(13)·15H(2)O (loeweite) were synthesized and their Raman spectra reported. By slow vaporization (at 20 °C and relative humidity of 60-70%), crystallization experiments were performed within small droplets (diameter ≤ 1-2 mm) of solutions containing MgSO(4) and Na(2)SO(4), and crystal formations were studied by Raman spectroscopy. Crystallization of Na(2)Mg(SO(4))(2)·4H(2)O (bloedite) was observed, and the formation of salt mixtures was confirmed by Raman spectra. Bloedite, konyaite, and loeweite, as well as Na(2)SO(4) and MgSO(4)·6H(2)O, were the components found to occur in different proportions. No crystallization of Na(6)Mg(SO(4))(4) (vanthoffite) was observed under the crystallization condition used in this study.     

PEO-[M(CN)5NO](x-) (M = Fe, Mn, or Cr) interaction as a driving force in the partitioning of the pentacyanonitrosylmetallate anion in ATPS: strong effect of the central atom

The partitioning behavior of pentacyanonitrosilmetallate complexes[Fe(CN) 5NO] (2-), [Mn(CN) 5NO] (3-), and [Cr(CN) 5NO] (3-)has been studied in aqueous two-phase systems (ATPS) formed by adding poly(ethylene oxide) (PEO; 4000 g mol (-1)) to an aqueous salt solution (Li 2SO 4, Na 2SO 4, CuSO 4, or ZnSO 4). The complexes partition coefficients ( K complex) in each of these ATPS have been determined as a function of increasing tie-line length (TLL) and temperature. Unlike the partition behavior of most ions, [Fe(CN) 5NO] (2-) and [Mn(CN) 5NO] (3-) anions are concentrated in the polymer-rich phase with K values depending on the nature of the central atom as follows: K [ F e ( C N ) 5 N O ] 2 - > K [ M n ( C N ) 5 N O ] 3 - > K [ C r ( C N ) 5 N O ] 3 - . The effect of ATPS salts in the complex partitioning behavior has also been verified following the order Li 2SO 4 > Na 2SO 4 > ZnSO 4. Thermodynamic analysis revealed that the presence of anions in the polymer-rich phase is caused by an EO-[M(CN) 5NO] ( x- ) (M = Fe, Mn, or Cr) enthalpic interaction. However, when this enthalpic interaction is weak, as in the case of the [Cr(CN) 5NO] (3-) anion ( K [ C r ( C N ) 5 N O ] 3 - < 1), entropic driving forces dominate the transfer process, then causing the anions to concentrate in the salt-rich phase.     

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.     

Effects of inorganic ions on the binding of triflupromazine and chlorpromazine to bovine serum albumin studied by spectrometric methods

The effects of inorganic salts, NaCl, NaBr, NaI, Na2SO4, KCl, KBr, KI, on the binding constants (Ks) of psychotropic phenothiazine drugs, triflupromazine (TFZ) and chlorpromazine, to bovine serum albumin (BSA) were examined by using second-derivative spectrophotometry. All of the salts examined, with the exception of Na2SO4, decreased the K values significantly, depending on the concentration of the salt, e.g., the decrease in the K values of both drugs were about 40% for 0.1 M NaCl. The results obtained with Na2SO4 indicated that neither Na+ nor SO4(2-) had any affect on the binding of the phenothiazines to BSA. Based on the Na2SO4 results and the finding that the effect of each potassium salt on binding was quite similar to that of the corresponding sodium salt, the effects of these halogen salts can be considered to be derived from their anions, although the phenothiazines are positively charged at pH 7.4. The effectiveness of the anions was determined to occur in the following order: I->Br->Cl-; these results coincided with the published order of the binding affinity of these anions to albumin. The 19F-NMR spectra of TFZ in the presence of each of these halogen salts revealed a concentration-dependent decrease in the intensity of the signal at 13.8 ppm that had previously been assigned to the TFZ bound to Site II. Consequently, the effects of these anions on the binding of positively charged phenothiazine drugs are thought to be local steric effects caused by the binding of these anions to Site II.     

外加盐作用形成的正负离子表面活性剂双水相

癸基三乙基溴化铵-癸基磺酸钠（C10NE-C10SO3）等摩尔混合均相体系（即使在表面活性剂总浓度高达0.2 mol•L－1时仍然可形成稳定的均相溶液）在外加盐NaF、Na2SO4和Na3PO4的作用下可自发分离成两个水相（双水相）.研究了该类双水相体系的形成、相行为及其对牛血清蛋白（BSA）的分配，并与普通的正负离子表面活性剂混合双水相体系进行了比较.结果表明，该类双水相体系克服了普通的正负离子表面活性剂混合双水相体系的一些不足，具有一些独特的优点.该类双水相体系的相行为可以通过外加盐进行调控,通过外加盐的种类来调控和优化BSA的分配行为.图1表2参8     

273 K下Na2CO3-Na2SO4-Na2B4O7-H2O四元体系介稳相平衡的实验研究

采用等温蒸发法研究了四元体系Na2CO3-Na2SO4-Na2B4O7-H2O在273 K时的介稳相平衡及平衡液相的密度. 利用溶解度数据绘制了该四元体系273 K下的相图. 研究结果表明, 该四元体系有异成分复盐2Na2SO4·Na2CO3形成. 相图中有2个共饱点、5条单变量曲线和4个结晶相区. 4个结晶相区分别为盐Na2CO3·10H2O, Na2SO4·10H2O, Na2B4O7·10H2O和2Na2SO4·Na2CO3的结晶区. 复盐2Na2SO4·Na2CO3同时存在于包含Na2CO3-Na2SO4-H2O三元体系的其它四元体系或高元体系中. 在273 K介稳平衡相图中, 碳酸钠以Na2CO3·10H2O形式析出; 硫酸钠以Na2SO4·10H2O的形式析出; 硼酸钠的完整分子式为Na2B4O5(OH)4·8H2O. Na2CO3对Na2B4O7有盐析作用.     

金属离子Na+,Li+及Mg2+与C1O4-和NO3-形成的无水离子缔合物种的从头算量子化学研究

采用量子化学计算方法在B3 LYP/6-311++G**水平下对Na+,Li+和Mg2+与ClO4-和NO3-形成的离子缔合物种的结构以及v1-频率进行了研究,并将结果与SO42-和上述3种阳离子形成的物种进行了对比.在缔合物种结构方面,当阳离子数目≤2时,与SO42-体系相似,ClO4-和NO3-主要与阳离子形成双齿缔合结构,而当阳离子数目＞2时,特别是具有2个正电荷的Mg2+离子数目较多时,由于阳离子间的斥力更大,与阳离 子结合能力较弱的ClO4-和NO3-较难与其形成稳定的离子团簇,而在SO42-体系中,则易形成单齿缔合结构.在v1-频率的变化趋势方面,3种阴离子形成的缔合物种大体相同,说明无水离子团簇的频率变化主要受阳离子性质和缔合结构影响.虽然阴离子性质也有部分影响,但不占主要地位.     

MgSO4-Na2SO4-H2O三元体系100 ℃沸腾蒸发非平衡态成盐特征

采用140 ℃恒温热源, 对MgSO4-Na2SO4-H2O体系溶液进行100 ℃恒温沸腾蒸发, 蒸发强度为140～160 g/(h&#8226;L), 监测初始析盐点和固相析出后固液相组成随蒸发进程的变化, 总结成盐特征, 提出反映非平衡态成盐特征的初级成盐区、扩展成盐区等概念. 研究发现(1)平衡相图上的同成分复盐3Na2SO4&#8226; MgSO4和Na2SO4&#8226; MgSO4&#8226;2.5H2O变为异成分复盐; (2)对Na2SO4和3Na2SO4&#8226;MgSO4的平衡共饱和液蒸发, 首先析出的是Na2SO4, 其单固相析出率为60.86%, 3Na2SO4&#8226;MgSO4和Na2SO4&#8226;MgSO4&#8226;2.5H2O的共饱和液也具有相同特征; (3)蒸发过程的初级成盐区与溶解平衡相区有显著区别. 用硫酸钠的耶涅克指数表示相区宽度, Na2SO4初级成盐区宽度从平衡态的21.02扩大到32.76; 而Na2SO4&#8226;MgSO4&#8226;2.5H2O则从41.40缩减为25.71; (4)在晶种存在的条件下, 各种盐的成盐区比初级成盐区有不同程度的扩展, 如Na2SO4, 3Na2SO4&#8226;MgSO4等盐的成盐区分别扩展了7.72和8.81. 扩展成盐区与初级成盐区的交叠形成了非平衡条件下特有的条件成盐区, 析盐种类取决于晶种的种类.     

高时空分辨率研究海盐液滴快速风化过程

以高速摄像仪与显微拉曼光谱联用研究聚四氟(疏水)乙烯基底和石英(亲水)基底上的单个海水液滴的快速风化过程.海水液滴风化的形貌图像达到毫秒时间分辨率和微米空间分辨率.通入干氮气后海水液滴在石英基底上发生快速风化过程,首先析出Na2Ca5(SO4)6·3H2O和Na2xCa8-x(SO4)6·3H2O(0＜x＜1)晶体,然后析出NaCI晶体,最后析出KMgCl3·6H2O晶体.我们发现在快速降低湿度的过程中析出钙钠复盐,在缓慢降低湿度的过程中析出CaSO4·2H2O,并已经确定各种结晶产物的位置以及Na2Ca5(SO4)6·3H2O和CaSO4· 2H2O两种晶体的生长速率,并在聚四氟乙烯基底上观察到中空结构的海盐颗粒.     

Effect of background electrolytes and pH on the adsorption of Cu(II)/EDTA onto TiO2

Cu(II)/EDTA adsorption onto TiO2 has been studied with a variation of pH, ionic strength, and type of background electrolytes. Cu(II) adsorption onto TiO2 increased as ionic strength increased when NaClO4 was used as a background electrolyte. This can be explained by the increase of exp(-FPsi/RT) as a part of the electrostatic correction within a surface complexation model. Model predictions described experimental adsorption trends. Types of background anions (ClO4, Cl, NO2, NO3, SO3, and PO4) did not affect adsorption trends and adsorption amounts of Cu(II) onto TiO2. However, different trends were observed with various types of background ions used as ionic strength in EDTA and Cu(II)-EDTA adsorption. EDTA adsorption was decreased by using Na2SO3 and Na3PO4 as background ions, while NaClO4, NaCl, NaNO2, and NaNO3 showed negligible interference on the EDTA adsorption, which matched well with model predictions. The presence Na2SO3 and Na3PO4 also interfered with Cu(II)-EDTA adsorption, to a somewhat greater extent compared to EDTA adsorption, especially at lower pH. This interference was also noted in Cu(II)-EDTA adsorption with a variation of Cu(II)-EDTA concentration at constant ionic strength (3 x 10(-3) M) by using Na2SO3 and Na3PO4, especially at lower ratios of Cu(II)-EDTA to Na2SO3 and Na3PO4. These results suggest that the ratio of Cu(II)-EDTA to Na2SO3 and Na3PO4 is an important factor for the controlling of competition between these background ions and Cu(II)-EDTA onto TiO2. Model prediction generally matched well with experimental adsorption using NaClO4, NaCl, NaNO2, and NaNO3 as backgrounds ions, while a severe deviation was observed in the presence of Na2SO3 and Na3PO4. These results suggest that the mobility of copper ions as Cu(II)-EDTA can be increased from polluted area in the presence of multivalent background ions, especially as the ratio of adsorbates/background ions decreased.