Effect of cetyltrimethylammonium bromide on morphology and porous structure of mesoporous hydroxyapatite

The mesoporous hydroxyapatite （HA） was synthesized by hydrothermal method utilizing cationic surfactant cetyltrimethylammonium bromide （CTAB） as template. The crystalline phase, morphology and porous structure were characterized respectively by different detecting techniques. The results reveal that the particles are highly crystalline hydroxyapatite phase. The surfactant has little influence on the morphology of the crystals, but affects the porous structure obviously. The sample without CTAB has a low surface area not exceeding 33 m^2/g, and no distinct pores can be observed by TEM. While the samples obtained with the surfactant get better parameters. Numerous open-ended pores centered at 2-7 nm spread unequally on the surface of the hydroxyapatite nanorods. The N2 adsorption-desorption experiments show type IV isotherms with distinct hysteresis loops, illustrating the presence of mesoporous structure. When the mole ratio of CTAB to HA is 1：2, the sample has the largest surface area of 97.1 m^2/g and pore volume of 0.466 cm^3/g.

Cu(Ⅱ),Ni(Ⅱ)Complexation with Acid Alizarine Blue B in the Presence of Cetyltrimethylammonium Bromide

The coordination reactions of Cu（Ⅱ） and Ni（Ⅱ） with acid alizarine blue B （AABB） in the presence of cetyltrimethylammonium bromide （CTAB） micelle were investigated using the microsurface adsorptionspectral correction technique （MSASC）. The aggregation of AABB on CTAB followed the Langmuir isothermal adsorption law. The enrichment of AABB on CTAB sensitized the complexation between Cu（Ⅱ） or Ni（Ⅱ）and AABB. The binding ratio of AABB to CTAB was 1：2.5, and monomeric aggregate, AABB2CTAB5, was formed with an adsorption constant of 5.95×10^5 at 20 ℃ or 2.48×10^5 at 40 ℃. In the ternary complexation, the ratio of AABB：Cu and AABB：Ni were 1：1 and 1：2.5, respectively. Two types of aggregates, Cu2.AABB2·CTAB80 and Ni5.AABB2.CTAB80, were formed.

Interaction of cetyltrimethylammonium bromide with drug in aqueous/electrolyte solution:A combined conductometric and molecular dynamics method study

Interaction between beta-lactum antibiotic drug ciprofloxacin hydrochloride(CFH)and cationic surfactant cetyltrimethylammonium bromide(CTAB)was performed conductometrically in aqueous as well as in the occurrence of different salts(NaCl,KCl as well as NH_4Cl)over the temperature range of 298.15–323.15 K at the regular interval of 5 K.CFH drug has been suggested for the treatment of bacterial infections such as urinary tract infections and acute sinusitis.A clear critical micelle concentration(CMC)was obtained for pure CTAB as well as(CFH+CTAB)mixed systems.The decrease in CMC values of CTAB caused by the addition of CFH reveals the existence of the interaction between the components and therefore it is the indication of micelle formation at lower concentration of CTAB and their CMC values further decrease in attendance of salts.A nonlinear behavior in the CMC versus T plot was observed in all the cases.The ΔG_m^0 values are found to be negative in present study systems demonstrated the stability of the solution.The values of ΔH_m^0 and ΔS_m^0 reveal the existence of hydrophobic and electrostatic interactions between CFH and CTAB.The thermodynamic properties of transfer for the micellization were also evaluated and discussed in detail.Molecular dynamic simulation disclosed that environment of water and salts have impact on the hydrophobic interaction between CFH and CTAB.In water and salts,CTAB adopts spherical micelle in which charged hydrophilic groups are interacted with waters whereas hydrophobic tails form the core of the micelle.This hydrophobic core region is highly conserved and protected.In addition,micelle formation is more favorable in aqueous Na Cl solution than other solutions.

Determination of Proteins by Measuring Total Internal-reflected Resonance Light Scattering Signals on Water/Tetrachloromethane Interface with Evans Blue and Cetyltrimethylammonium Bromide

A sensitive and selective assay of proteins is proposed based on measuring the total internal-reflected resonance light scattering(TIR-RLS) signals produced on the water/tetrachloromethane(H_2O/CCl_4) interface. In an aqueous medium with pH value in the range of 3.29—3.78, electrostatic attraction occurs between the negatively charged Evans Blue(EB) and positively charged proteins, forming hydrophobic ion associates and resulting in EB-protein adsorption on H_2O/CCl_4 interface. The presence of cetyltrimethylammonium bromide prompts this adsorption, resulting in strongly enhanced TIR-RLS signals. The intensity of the enhanced TIR-RLS at 360—370 nm was found to be proportional to the concentration of proteins. For bovine serum albumin and human serum albumin, the linear range of detection is 0.07—1.2 μg/mL and the limits of detection are 6.68 and 6.30 ng/mL(3σ), respectively, while for lysozyme, the linear range of detection is 0.06—1.0 μg/mL and the limit of detection is 6.0 ng/mL(3σ). The content of the total albumin in a human urine sample could be directly determined by using the standard addition method with a percent recovery of 97.6%—104.1%, and the RSD ranging from 1.9% to 4.2%.

Spectrofluorimetric Determination of Tetracycline Using Eu^(3+)Chelation and Cetyltrimethylammonium Bromide

The fluorescence of tetracycline was greatly enhanced by chelation with Eu 3+ in Tris HCl buffer (pH8.5). The addition of cetyltrimethylammonium bromide, a cationic surfactant, further enhanced the fluorescence of tetracycline Eu 3+ chelates.This spectrofluorimetric method for the determination of tetracycline yielded a linear responeses in the range of 10 nmol/L 10 μmol/L. The detection limit was 5 nmol/L (or 2.22 ng/mL).The recovery of tetracycline spiked in serum at levels of l and 0.09 μg/mL was 97.9% and 97.8%, respectively. This method is fast, sensitive and suitable for the determination of tetracycline in biological specimens.

Novel Approach to Characterization of Rare Earth Complexation with 1, 5-Bis(2-Hydroxy-5-Chlorphenyl)-3-Cyanoformazan in Presence of Cetyltrimethylammonium Bromide

The ternary interaction of 1, 5 bis(2 hydroxy 5 chlorphenyl) 3 cyanoformazan (HCPCF) with cetyltrimethylammonium bromide (CTAB) and rare earths (RE: Yb, Dy, Er and Eu) was investigated at pH 9.84 by the microsurface adsorption spectral correction technique (MSASC). The aggregation of HCPCF on CTAB obeys the Langmuir isothermal adsorption and the interaction of RE with the HCPCF CTAB aggregate was first found to accord with the monolayer binding. The effects of temperature and ionic strength of solution on the aggregations were made. The binary aggregate and the ternary complex were characterized.

Investigation of Surfactant-Stain-Metal Interaction: Naphthochrome Green/Cetyltrimethylammonium Bromide/Rare Earths Ternary Complexation

The ternary interaction of naphthochrome green (NCG) with cetyltrimethylammonium bromide (CTAB) and rare earths (REs: Yb, Dy, Er and Eu) has been investigated with the microsurface adsorptionspectral correction technique (MSASC). The aggregation of NCG on CTAB obeys the Langmuir isothermal adsorption. The enrichment of NCG on CTAB and the presence of NaCl sensitize the complexation between REs and NCG. Both the binary aggregate and the ternary complex were characterized in the presence and absence of NaCl at pH 8.30 at 20 and 40C.

DES+CTAB复配驱油剂体系提高低渗致密砂岩油藏采收率机理

针对低渗致密油藏注水困难、采收率低等问题,利用尿素基深共晶溶剂(DES)与十六烷基三甲基溴化铵(CTAB)复配的驱油剂体系,对驱油剂在低渗致密油藏中的降压增注和提高采收率机理进行了研究。研究结果表明:①驱油剂体系可以将油水界面张力降低至10^(-3)mN/m以下,大大提高了洗油效率;②驱油剂体系可有效抑制黏土矿物水化,避免了低渗致密砂岩中黏土矿物水化膨胀带来的流体敏感性损害;③驱油剂体系可对砂岩表面进行界面修饰,驱油剂溶液浸泡后样品的油相接触角由25.8°增加至61.4°,亲水性增强,亲油性减弱,有助于吸附在岩石孔隙壁面的油膜脱落;④超前注入驱油剂的注入压力降低率平均为79.64%,采收率平均为50.96%,远大于常规水驱(一次注水→注驱油剂驱→二次注水)的采收率。

CTMAB和PDMDAAC有机改性膨润土的制备及其表征

以天然膨润土为原料,进行提纯钠化,得到钠化膨润土,测定了其膨胀容、膨润值、胶质价、吸蓝量、阳离子交换容量等指标,使提纯钠化后的膨润土性能更加优越。分别以溴化十六烷基三甲基铵(CT-MAB)和聚二甲基二烯丙基氯化铵(PDMDAAC)作为有机插层剂制备了两种有机改性膨润土,通过傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)和BET表面积及孔隙度分析对改性膨润土进行表征。XRD结果表明CTMAB和PDMDAAC有机改性膨润土具有膨润土的特征衍射峰,d001值分别增大到1.89和1.45nm,结合FTIR谱图中CH2振动峰的出现,说明两种插层剂已经进入到膨润土层间。有机改性膨润土的比表面积、孔隙体积和平均孔径相比钠化膨润土均有所降低。

基于MSEP@CTAB的磁固相萃取结合HPLC-UV法测定环境水和饮品中的苏丹红

目的制备一种有机/无机双功能化磁性纳米复合材料MSEP@CTAB,将其作为磁固相萃取的吸附剂并结合HPLC-UV法检测环境水和饮品中的苏丹红残留。方法以Fe_(3)O_(4)作为磁性纳米粒子,选择海泡石(Sepiolite,SEP)为无机材料对其进行修饰,再采用十六烷基三甲基溴化铵(cetyltrimethylammonium bromide,CTAB)进行有机改性,得到有机/无机双功能化磁性纳米复合材料MSEP@CTAB;利用傅里叶变换红外光谱仪、透射电子显微镜、X射线衍射仪、振动样品磁力针和全自动比表面及孔隙度分析仪等对复合材料进行表征;考察并优化磁固相萃取条件。结果在最佳实验条件下,3种苏丹红染料在质量浓度0.5~50 ng·mL^(-1)内线性关系良好(R^(2)≥0.9962),检测限为0.05~0.07 ng·mL^(-1),定量限为0.17~0.23 ng·mL^(-1),日内和日间精密度分别为1.8%~8.8%和2.8%~9.0%。该方法被成功应用于环境水和饮品中3种苏丹红染料的检测,加标回收率为82.5%~108.2%。结论所建立的方法简便、快速、灵敏,为环境水和饮品中痕量苏丹红染料的检测提供了一种可行的策略。

十六烷基三甲基溴化铵对电镀铜-镍合金耐蚀性的影响

[目的]研究Cu-Ni合金电镀液中添加不同质量浓度的十六烷基三甲基溴化铵(CTAB)对Cu-Ni合金镀层耐蚀性的影响。[方法]通过浸泡腐蚀试验、塔菲尔极化曲线测试和电化学阻抗谱(EIS)考察了Cu-Ni合金镀层的耐蚀性。通过扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)分析了Cu-Ni合金镀层的表面形貌、成分和晶相结构。采用傅里叶变换红外光谱仪(FTIR)分析了CTAB在Cu-Ni合金镀层中的夹杂情况,并通过接触角测量研究了Cu-Ni合金镀层的疏水性。此外,根据阴极极化曲线测试结果,研究了CTAB质量浓度对Cu、Ni及Cu-Ni合金电沉积行为的影响。[结果]随着镀液中CTAB质量浓度增大,Cu-Ni合金镀层的耐蚀性先变好后变差。CTAB质量浓度为80mg/L时所得Cu-Ni合金镀层表面呈花椰菜状的空间立体形貌,镀层中Cu、Ni质量分数分别为50.25%和40.86%,对腐蚀液的接触角达到129.49°,耐蚀性最佳。[结论]镀液中添加适量CTAB能够显著提高Cu-Ni合金镀层的耐蚀性。

4,5二溴苯基萤光酮-CTMAB测定镁的分光光度法研究

本文研究了在CTMAB存在下,镁和4,5二溴苯基萤光酮(Br-PF)的显色反应。结果表明,在碱性介质中镁(Ⅱ)和Br-PF及CTMAB形成了蓝紫色的高灵敏的三元配合物,其表观摩尔吸光系数为1.16×10~5L·mol^(-1)·cm^(-1)(λ_(max)=645nm),镁(Ⅱ)对Br-PF的摩尔比1∶2。镁浓度在0—1.5μg/10ml遵守比尔定律。用拟定的方法测定了硅酸岩、铝合金和锌合金中的镁,得到了满意的结果。

银纳米粒子共振光散射光谱法测定痕量CTMAB

利用十六烷基三甲基溴化铵（CTMAB）与银纳米粒子作用生成的聚集体,使体系的共振光散射（RLS）强度明显增强,建立了-种快速、简便的测定痕量CTMAB 的RLS 光谱法.考察了pH 值,反应最佳时间,试剂加入顺序等因素对测定CTMAB 的影响.实验结果表明,在pH 值为10. 88,作用时间为10 min,银纳米粒子浓度（以银原子计算）为2. 5×10^-3 mol·L^-1 ,按CTMAB、BR、银纳米粒子为添加顺序的条件下,测定CTMAB 的线性范围为：5. 0×10^-9 -5. 0×10^-7 mol·L^-1 ,检出限为3. 8×10^-9 mol·L^-1 .该法用于合成样品中CTMAB 的测定,灵敏度高,重现性好,结果准确.

CTMAB-13X分子筛的制备及对水中甲基橙的吸附

用十六烷基三甲基溴化铵(CTMAB)对13X分子筛进行改性制备CTMAB-13X分子筛,研究了不同条件下CTMAB-13X分子筛对废水中甲基橙的吸附性能、影响因素及动力学过程。结果表明:CTMAB-13X分子筛投加量为0.1 g/L,吸附时间10 min后对甲基橙吸附可达平衡,此时去除率达到88.9%。CTMAB-13X分子筛吸附容量为275mg/g,高于活性炭的182 mg/g。Zeta电位分析说明经阳离子表面活性剂CTMAB改性的13X分子筛表面带正电,对水中带负电的酸性染料甲基橙有较强的吸附效果。由红外吸收光谱(FTIR)看出CTMAB的特征峰出现在CTMAB-13X分子筛中,说明CTMAB接枝改性到13X分子筛表面。分析X-射线图谱得出CTMAB改性剂没有破坏13X分子筛自身的晶体结构,进一步证明CTMAB是接枝在分子筛表面。从扫描电镜(SEM)可以看出改性后的CTMAB-13X分子筛更为分散,因此可以为染料分子提供更多的吸附点位。激光粒度测定结果表明CTMAB-13X分子筛平均粒径D av由17.45μm下降到12.41μm,比表面积(S/V)由5143.69 cm2/cm3增大到7752.48 cm2/cm3,与SEM分析结果一致。

CTMAB增敏荧光光度法测定牛奶中莫西沙星残留量

基于在pH 5.00的柠檬酸盐缓冲溶液中,十六烷基三甲基溴化铵(CTMAB)可使莫西沙星(MXFX)-钇(Ⅲ)反应体系的荧光强度显著增敏,提出了荧光光度法测定牛奶中MXFX残留量的分析方法。在292nm(λ_(ex))及483nm(λ_(em))波长处,所测得的相对荧光强度与MXFX的质量浓度在50～800μg·L^(-1)范围内呈线性关系。方法的检出限(3σ)为46.2μg·L^(-1)。方法用于牛奶中MXFX的测定,测得方法的平均回收率为92.8%,测定值的相对标准偏差(n=5)均小于3%。

CdS-BSA-CTMAB荧光光度法测定食品中蛋白质的含量

实验以六偏磷酸钠为稳定剂,巯基乙酸为修饰剂水相合成了荧光试剂CdS量子点。结果表明,牛血清白蛋白(BSA)可使CdS的荧光峰增强,而阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)的加入,可使体系荧光峰显著增敏,并且荧光强度与BSA浓度在8.0×10-5～1.3mg/mL范围内呈良好的线性关系,回归方程为F=1486.94793+937.70328C,相关系数R=0.9957,检出限为7.4×10-5mg/mL。方法已用于食品中蛋白质的测定,与考马斯亮蓝法对照,结果满意。

CTMAB增强调控沉积物(生物膜)吸附BPA的作用

研究了经十二烷基苯磺酸钠（SDBS）、曲拉通（TX-100）和十六烷基三甲基溴化铵（CTMAB）改性前后的沉积物（生物膜）吸附双酚A（BPA）的能力,并分析了CTMAB在沉积物（生物膜）吸附BPA过程中的增强机理及表面吸附和分配作用在总吸附中的贡献。研究结果表明,三种表面活性剂对沉积物（生物膜）吸附BPA的促进作用大小依次为：CTMAB〉TX-100〉SDBS,经CTMAB改性的沉积物（生物膜）对水中BPA的去除率最高可达44.14%（56.95%）。沉积物（生物膜）对BPA的吸附行为可利用吸附-分配复合模式描述（r均大于0.98）。在BPA平衡浓度为0.01~0.81 mg/L范围内,随着CTMAB浓度的增大沉积物（生物膜）吸附BPA的分配作用的贡献也呈增大趋势,与表观分配系数变化趋势一致,表面吸附贡献在总吸附过程中仍占主导地位（沉积物〉87.38%;生物膜〉66.32%）。

碘化物-CTMAB体系共振光散射法测定铋

用简易荧光计研究了在微酸性介质中，铋-碘化钾-十六烷基三甲基溴化铵（CTMAB）体系的共振光散射光谱，考查了光谱特征、影响因素和适宜的反应条件；确定了散射光强度与溶液中铋浓度的关系，提出了共振光散射法测定铋的方法；该法在室温下进行，线性范围为0．2～0．6mg·L^-1，方法的检出限0．003mg·L^-1；用于胃药中铋的测定，并在此样品的基础上加入铋（Ⅲ）标准进行了回收试验，得回收率结果为107．3％。

姜黄素-La^(3+)-CTMAB-核酸体系的荧光增强效应及其应用

研究了镧离子(La3+)-姜黄素(CU)-十六烷基三甲基溴化铵(CTMAB)-核酸荧光增强体系。建立了测定核酸的新方法。体系的最优条件为:六次甲基四胺(HMTA)-HCl缓冲溶液(pH 5.80)中,1.00×10-3mol/L阳离子表面活性剂CTMAB存在下,姜黄素浓度为2.00×10-5mol/L,La3+的浓度为1.40×10-4mol/L时,核酸能增强La3+-CU络合物的荧光强度,而且体系荧光的增强程度与核酸的加入量在一定范围内呈线性关系。fs-DNA,ctDNA和yRNA线性范围分别为7.00×10-4～10.00 mg/L,4.00×10-4～10.00 mg/L和7.00×10-4～10.00 mg/L;检出限分别为0.17,0.02和0.14μg/L。与已报道的核酸的分析方法相比,本方法具有较宽的线性范围和较高的灵敏度。研究表明,核酸对体系荧光的增强源于DNA主链上PO34-与CU之间的静电结合,以及通过氢键和疏水力进行的沟槽式结合,为探针分子提供了疏水性的微环境,降低了体系的非辐射能量损失,使体系的荧光强度增加。

锌制剂的PAR-CTMAB比色测定法

对测定锌制剂含量的PAR-CTMAB比色法进行了研究。本法简便、快速,结果准确,重现性好,线性范围宽(0.08～1.2μg/ml),且干扰小,回收率为100.1±0.25%。本法同中国药典法比较,测定结果经F、t 测验无显著差异。