共查询到17条相似文献,搜索用时 218 毫秒
1.
以P(St-Am·MG)对染料活性艳红(X-3B)溶液进行絮凝试验,考察了高聚物剂量及外加盐对絮凝效果的影响,并与无疏水基团的阳离子聚丙烯酰胺PAm·MG的絮凝能力进行了比较。发现絮凝体系无外加盐时,高聚物与染料的作用主要是通过静电力;有外加盐时,高聚物的电荷受到屏蔽,高分子链卷曲,PAm·MG的絮凝效果受到较大影响。而P(St-Am·MG)与X-3B之间存在疏水相互作用,受影响较小,此时P(St-Am·MG)的絮凝性能优于PAm·MG。用平衡渗析法研究了不同温度时甲醇和脲存在下P(St-Am·MG)与X-3B相互作用的热力学。证明了它们之间确实存在疏水相互作用。 相似文献
2.
用平衡渗析法研究了主链含疏水基、侧链含亲水基的接枝共聚物P-M-St和二氰二胺同甲醛、氧化铵的缩合物D-F与甲基橙MO及乙基橙EO,橙黄ⅣO-Ⅳ相互作用的热力学.由Klotz方程求得键合常数K 1和△G、△H和△S.D-F与P-M-St相比,其与MO的键合作用较弱.P-M-St与染料的键合程度:O-Ⅳ>EO>MO.脲或甲醇能削弱高聚物与染料的相互作用. 相似文献
3.
以 AIBN为引发剂,丙烯酰胺与苯乙烯在1 4—二氧六环溶剂中进行共聚,得到无规共聚物P(St-Am)。使P(St-Am)与过量甲醛反应,生成羟甲基化产物。该产物在酸性条件下进一步与二氰二胺反应,制得分子链上同时含有离子和疏水基团的高分子苯乙烯—丙烯酰胺基甲撑脒基脲盐酸盐共聚物P(St-Am·MG)。P(St-Am) 和P(St-Am·MG) 的结构用红外光谱法鉴定,组成用元素分析法测定。 P(St-Am·MG) 在 MeOH/H_2O混合溶剂中的粘性行为表明它是带有疏水基的聚电解质,用电导滴定法和小角激光光散射法分别测定其电荷密度和分子量。 相似文献
4.
用甲醛(F)和二氰二胺(D)改性聚丙烯酸胺(PAm),制得新型阳离子聚电解质PAm·MG,对PAm·MG的合成和表征进行了研究。合成反应通过两步进行,先使PAm与F反应,生成羟甲基化产物PAm·M,然后在酸性条件下使PAm·M与D反应,制得PAm·MG.控制F用量,得到不同取代度的PAm·M.和PAm·MG。PAm·MG在水溶液中能与阴离子聚电解质形成复合物沉淀证明PAm·MG带有阳离子基团。元素分析及电位、浊度滴定结果表明PAm·M中的羟基完全与D发生了反应。SALLS测得的M_w证实了PAm在改性过程中分子链未发生降解。 相似文献
5.
前文曾报导,以聚丙烯酰胺为母体,通过甲醛为桥梁引入二氰二胺可合成一种新型阳离子聚电解质,简称PAm·MG,它是一种弱聚碱的盐酸盐,结构式如下(S 为取代度):PAm·MG 对含活性艳红染料的废水有明显的絮凝脱色作用,其絮凝效果受聚合物的取代度、介质的pH 以及外加盐浓度的影响,而这些影响因素又直接与聚碱的离解行为或胺基离子化度(指已离子化的胺基占全部胺基的分数)密切相关.为此,本文对影响PAm·MG 离解行为和离子化度的一些因素作进一步探讨,并通过粘度测定考察离解行为对聚合物在水中形态的影响,为PAm·MG 的实际应用提供理论根据. 相似文献
6.
利用荧光光谱法及紫外吸收光谱法结合计算机模拟技术研究了在模拟生理条件下胡椒碱(piperine)与牛血清白蛋白(Bovine Serum Albumin, BSA)的相互作用. 根据荧光猝灭的有关方程分别求得不同温度下(298, 308和318 K)药物与蛋白相互作用的结合常数、结合位点数及键合距离. 实验所得到的热力学参数(ΔH 1256;=-9.55 kJ/mol, ΔS 1256;=46.75 J 8226;mol-1 8226;K-1)表明维持药物与蛋白质的相互作用力主要是疏水作用和静电作用. 分子模拟的结果显示了胡椒碱与BSA的键合机理和键合模式, 表明维持药物与蛋白质的相互作用力主要是疏水作用和氢键(位于氨基酸残基His 242, Arg 222和Arg 218位). 此外, 基于胡椒碱的荧光猝灭效应, 首次探讨了药物-蛋白质体系的几种物理化学参数, 包括电荷密度(δ)、离解常数(Kd)及量子产率(F)的变化效应. 相似文献
7.
在25℃用荧光和紫外光谱滴定法分别测定了β-环糊精(β-CD)、2,3,6-三[氧-(2-羟基丙基)]-β-环糊精(HP-β-CD)及2,3,6-三(甲氧基)-β-环糊精(MO-β-CD)与6种脂肪族手性客体和4种染料分子形成超分子配合物的稳定常数.结果表明,多种弱相互作用协同贡献于主-客体的包结配位过程.环糊精衍生物中取代基的疏水性和链长影响主体的配位能力,客体与环糊精间的尺寸适合及疏水相互作用决定其配合物的稳定性.在配位过程中,氢键作用也是影响主体环糊精键合行为的重要因素. 相似文献
8.
在模拟人体生理条件下,结合紫外光谱和分子对接模型运用荧光光谱研究了腺苷与人血清白蛋白(HSA)间的键合作用。腺苷有较强的能力猝灭人血清白蛋白的内源荧光,且根据Stern-Volmer方程判断出猝灭机制为静态猝灭。本文运用相应的荧光值和Vant’Hoff热力学方程求得了不同温度下的结合常数(K)以及一些热力学参数,如焓变(ΔH)和熵变(ΔS)。结果表明:键合过程中疏水作用力对新化合物的稳定性起主要作用,这与分子对接模型方法研究的结果基本一致。另外还研究了常见离子对结合常数的影响。 相似文献
9.
将互为同分异构体的两种植物药活性组分补骨脂素和异补骨脂素作为研究对象,利用荧光光谱、紫外光谱、圆二色谱及傅立叶变换红外光谱详细比较研究了这两种香豆素类化合物与人血清白蛋白(HSA)的键合作用.不同光谱的结果定性、定量地显示了HSA二级结构变化的程度.依据荧光滴定实验及Van′t Hoff公式求出了反应的热力学参数(ΔH和ΔS)的值.根据修正后的Stern-Volmer和Scatchard方程和荧光光谱数据分别求得不同温度(296,303,310及318 K)下药物与蛋白相互作用的结合常数及结合位点数;且根据F觟rster偶极-偶极能量转移理论,求得药物与HSA间的键合距离;利用竞争实验确定了药物在HSA上的键合位点为site II.从分子水平上揭示了这两种化合物与HSA相互作用的机制. 相似文献
10.
利用计算机模拟技术结合荧光增敏光谱法、圆二色谱法及傅立叶红外光谱法研究了愈创木-酚与人免疫球蛋白的相互作用. 分子模拟结果显示了愈创木酚与HIgG(Human Immunoglobulin)的键合机理和键合模式, 表明维持药物与蛋白质的相互作用力主要是疏水作用和氢键(位于氨基酸残基LEU 80 和 ASP 65位). 这与实验所得到的热力学参数判定作用力的结果相一致(依据范德霍夫公式计算得DH 0与DS 0的值分别为65.55 kJ · mol -1和132.95 J · mol -1 · K -1). 根据荧光增敏和偏振的有关方程分别求得不同温度下药物与蛋白相互作用的结合常数及结合位点数; 从紫外光谱和同步荧光光谱获得的信息定性地讨论了药物与蛋白相互作用时药物对蛋白构型的影响, 圆二色谱法和红外光谱法(红外去卷积谱和曲线拟合)的结果得到了定量的蛋白质二级结构变化数据. 且利用Förster 能量转移理论, 求得药物与蛋白间的键合距离为4.57 nm. 此外, 基于愈创木酚的荧光敏化效应, 探讨了药物-蛋白质体系的几种物理化参数, 包括电荷密度、离解常数(p Ka)及量子产率的变化效应. 相似文献
11.
The binding of methyl orange, ethyl orange, and propyl orange by polycations involving various apolar pendant groups such as methyl, ethyl, benzyl, or dodecylbenzyl groups has been examined quantitatively by an equilibrium dialysis method at 5, 15, 25, and 35°C. The first binding constants and the thermodynamic parameters in the course of the binding have been calculated. The favorable free energy of the binding is accompanied by an entropy gain and an exothermic enthalpy change. The shorter the alkyl chain of the dyes or the polymers, the more negative is the enthalpy change and hence the smaller is the entropy change. Furthermore, an increase in binding affinity can be created in the polycation upon introduction of hydrophobic groups. In particular, the binding ability of the polycation containing a dodecylbenzyl group for methyl orange is almost 300-fold that of bovine serum albumin. Therefore it is clear that hydrophobic interactions, as well as electrostatic ones, are involved in the binding. 相似文献
12.
The present research combines biosorption and photocatalysis in a functional TiO(2)-immobilized chitosan adsorbent (CTA). CTA can degrade organic pollutants and adsorb metal ions simultaneously. Target pollutants were dyes of cationic (rhodamine B, Rh.B) and anionic (methyl orange, MO) nature, with Ni(2+) and Cu(2+) selected as heavy metals. The presence of Ni(2+) or Cu(2+) improved the degradation ability of CTA for MO, but inhibited the degradation of Rh.B, with Cu(2+) exhibiting stronger effects than Ni(2+). There was no significant difference in CTA activity when the metal ions were pre-adsorbed or when they coexisted in the solution with the organic dyes. Protons in the reaction system affected the degradation performance in a similar way for Ni(2+) and Cu(2+) leading to a different effect on the degradation for MO and Rh.B. An X-ray photoelectron spectroscopy analysis of the binding energies of the metal ions on the surface in the presence of the cationic or anionic dyes explained the different behaviors. Since anionic and cationic dyes possess chromogenic groups of different charges, they adversely affect the production of OH? radicals when coexisting with Cu(2+) or Ni(2+). 相似文献
13.
In this study, we describe a sensitive staining method for DNA in agarose and polyacrylamide gels using organic visible dyes, indoine blue (IB) and methyl orange (MO). The counterion-dye staining method uses two oppositely charged dyes to form a hydrophobic ion pair complex in the staining solution. A decrease in the number of free forms of dyes in staining solution can enhance the selectivity of binding between the dye and DNA, and can reduce nonspecific background staining. As a result, the sensitivity of counterion-dye staining was significantly improved compared with other dye-based staining. This method uses a staining solution consisting of 0.008% IB, 0.002% MO, 10% ethanol and 0.2 M sodium acetate at pH 4.7, and can detect 5 ng of lambda DNA/HindIII within 60 min in agarose gels and 10 ng of PhiX174 DNA/HaeIII within 20 min in polyacrylamide gels. 相似文献
14.
In this paper, a novel pipette tip micro-solid phase extraction based on molecularly imprinted polymer as a selective sorbent was developed and applied for extraction, pre-concentration and high-performance liquid chromatographic determination of trace amounts of malachite green (MG), rhodamine B (RB), methyl orange (MO) and acid red 18 (AR) dyes in seawater samples. Different parameters affecting the extraction efficiency such as type and volume of eluent solvent, sample volume, number of cycles of extraction and desorption, amount of sorbent and pH of the sample solution were evaluated using one-variable-at-a-time and response surface methodology. In order to optimize dyes extraction, seven factors in three levels were used for Box–Behnken experimental design. Under optimum extraction condition, pH of sample solution was 3.1 for MG, 3.0 for RB, 7.1 for MO and 6.1 for AR; volume of eluent solvent (HCl, 0.5 mol L−1) was 200 µL; volume of the sample solution was 10 mL (for MG) and 4 mL (for RB, MO and AR); the concentration of triton X-114 was 0.085 (MG), 0.10 (RB), 0.08 (MO) and 0.075 (AR) % v/v; the number of extraction cycles was 10 (MG), 6 (RB), 5 (MO) and 7 (AR); the number of elution cycles was 10, 6, 5 and 9, respectively, for MG, RB, MO and AR; NaCl concentration was 0.4 mol L−1; and amount of MIP was 2.0 mg for all dyes. The linear range of calibration curves was 0.5–250.0 µg L−1 for malachite green and methyl orange and 0.5–150.0 µg L−1 for both rhodamine B and acid red 18. The detection limits calculated to be 0.083, 0.10, 0.12 and 0.17 µg L−1 for MG, RB, MO and AR, respectively. The developed protocol was successfully used for determination of dyes in seawater of Chabahar Bay. The mean recoveries were ranged between 76.1 and 97.3% by mean relative standard deviations of 1.2–7.1%. 相似文献
15.
The binding of acid azo dyes having phenolic hydroxyl groups such as orange I ( I ), orange II ( II ), chrome violet ( III ), 4-hydroxyazobenzene-4′-sulfonate ( IV ), and 2,4-dihydroxyazobenzene-4′-sulfonate ( V ) by polyethylenimine was studied by equilibrium dialysis and spectroscopic methods. The results obtained indicate that dyes ( III ) and ( V ) with two OH groups are bound much more strongly than dyes ( I ), ( II ), and ( IV ) with one OH group. Also polyethylenimine is far superior to any other polymers which have been examined, including bovine serum albumin, polyvinylpyrrolidone, and poly-L -lysine, in its ability to form complexes with these dyes ( III ) and ( V ). The OH groups involved participate preferentially in complex formation with polyethylenimine. The unusual affinity of polyethylenimine for the dyes carrying OH groups is discussed. 相似文献
16.
研究了二安替比林对甲基苯基甲烷 (DAp MM)与 Ce( )的显色反应 ,在 H3PO4 介质中 ,DAp MM与 Ce( )生成橙色产物。λmax=485nm,ε=3.53× 1 0 5L·mol-1·cm-1。Ce( )含量在0 .5~ 8.0μg/2 5ml内符合比耳定律 ,该体系灵敏度高 ,选择性好 ,用于镁合金和含锌矿石中微量铈的测定 ,结果满意。 相似文献
17.
2-Diethylaminoethyl methacrylate (DEAEMA)– N-vinyl-2-pyrrolidone (VPy) copolymers of various compositions have been synthesized. The resultant copolymers were examined for their ability to bind methyl orange and its homologs, in particular butyl orange, at 5, 15, 25, and 35°C in aqueous solutions. The amount of binding of butyl orange is much higher with the copolymers than with polyvinylpyrrolidone or with 2-hydroxyethyl methacrylate– N-vinyl-2-pyrrolidone copolymers. Introduction of only 3% of the hydrophobic DEAEMA residue increases markedly the binding affinity toward the cosolute. Maximal binding is obtained at 15°C in the temperature range measured. This peculiar temperature dependence of the extent of binding is explicable on the basis of hydrophobic effects involved in this binding. The peculiar temperature dependence disappeared in aqueous solution of NaSCN which acts as a water-structure breaker: the extent of binding changes regularly with temperature. This is interpretable only in terms of reduction of hydrophobic contribution to the binding. With propyl orange, which is a less hydrophobic cosolute than butyl orange, the peculiarity of the binding was not detected. 相似文献
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