Efficient synthesis and sulfonation of ordered mesoporous carbon materials

Ordered mesoporous carbons (OMCs) with hexagonal structure were efficiently synthesized via cooperative self-assembly of phenol/formaldehyde resol and surfactant F127 under acidic aqueous conditions. Induced by HCl, a gel phase mainly containing phenol/formaldehyde resol and F127 was obtained within several hours. X-ray diffraction (XRD), transmission electron microscope (TEM) and nitrogen adsorption isotherms indicated that the synthesized samples possess 2-D hexagonal mesostructure. The influence of the synthesis conditions, including acid concentration and mass ratio of resol to F127, was investigated. When the acid concentration was fixed in the range of 0.6-2.0 M and the mass ratio of resol to F127 in the range of 3.5-4.0, highly ordered mesoporous carbon could be synthesized. The synthesized OMCs could be easily sulfonated in concentrated sulfuric acid at elevated temperature. The results indicate that the mesostructural stability and the content of the surface sulfonic acid (SO(3)H) groups depend mainly on the pyrolysis temperature of the OMCs and the sulfonation temperature, suggesting that the combination of pyrolysis and sulfonation temperature is essential for developing OMCs with high densities of SO(3)H groups.     

Electrochemical Oxidation and Detection of Morphine at Ordered Mesoporous Carbon Modified Glassy Carbon Electrodes

In this work, three ordered mesoporous carbons (OMCs) with different structural parameters were synthesized by a simple variation of the hydrothermal temperature of the silica templates (SBA‐15). X‐ray diffraction and nitrogen adsorption‐desorption results show these OMCs exhibit an ordered 2D hexagonal mesostructure with tunable pore diameter. OMC‐modified glassy carbon electrodes exhibit efficient electrocatalytic reactivity toward oxidation of morphine (MO). The amperometric detection of MO in pH 7.0 phosphate buffered saline at +0.39 V versus Ag/AgCl is the lowest potential reported to‐date. A linear range from 0.2 to 197.6 μM and a detection limit of 0.03 μM MO were obtained.     

Nonenzymatic amperometric sensor of hydrogen peroxide and glucose based on Pt nanoparticles/ordered mesoporous carbon nanocomposite

A simple and facile synthetic method to incorporate Pt nanoparticles inside the mesopores of ordered mesoporous carbons (OMCs) is reported. The Pt/OMCs nanocomposite was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and nitrogen adsorption-desorption. The results show that the incorporation of Pt nanoparticles inside the pores of OMCs does not change the highly ordered two-dimensional hexagonal mesostructure of OMCs matrix. Nonenzymatic amperometric sensor of hydrogen peroxide and glucose based on the Pt/OMCs nanocomposite-modified glassy carbon (GC) electrode is developed. Compared with the original OMCs-modified electrode, the Pt/OMCs-modified electrode displays improved current response towards hydrogen peroxide and gives linear range from 2 to 4212 μM. At an applied potential of −0.08 V, the Pt/OMCs nanocomposite gives linearity in the range of 0.5-4.5 mM glucose in neutral buffered saline solution. This glucose sensor also exhibits good ability of anti-interference to electroactive molecules. The combination the unique properties of Pt nanoparticles and the ordered mesostructure of OMCs matrix guarantees the enhanced response for hydrogen peroxide and glucose.     

Solution-phase synthesis of ordered mesoporous carbon as resonant-gravimetric sensing material for room-temperature H_2S detection

H_2S can cause multiple diseases and poses a great threat to human health.However,the precise detection of extremely toxic H_2S at room temperature is still a great challenge.Here,a facile solvent evaporation induced aggregating assembly(EIAA) method has been applied for the production of ordered mesoporous carbon(OMCs) in an acidic THF/H_2 O solution with high-molecular-weight poly(ethylene oxide)-b-polystyrene(PEO-b-PS) copolymers as the structure-directing agent,formaldehyde and resorcinol as carbon precursors.Along with the continuous evaporation of THF from the mixed solution,cylindrical micelles are formed in the solution and further assemble into highly ordered mesostructure.The obtained OMCs possesses a two-dimensional(2 D) hexagonal mesostructure with uniform and large pore diameter(～19.2 nm),high surface area(599 m~2/g),and large pore volume(0.92 cm~3/g).When being used as the resonant cantilever gas sensor for room-temperature H_2S detection,the OMCs has delivered not only a superior gas sensing performance with ultrafast re s ponse(14 s) and recovery(21 s) even at low concentration(2 ppm) but also an excellent selectivity toward H_2S among various common interfering gases.Moreover,the limit of detection is better than 0.2 ppm,indicating its potential application in environmental monitoring and health protection.     

分光光度法测定三氧化铀中的硫酸根

采用TBP-萃淋树脂吸附三氧化铀样品中的铀,硫酸根与铬酸钡进行交换反应后,直接比色法测定硫酸根的含量。实验中研究了三氧化铀样品中硫酸根含量测定的样品制备、分离、反应酸度,煮沸时间,铬酸钡用量等影响因素。优化条件下,采用硝酸(5mol/L)淋洗、1mL HCl溶液(2.5mol/L)调节溶液中酸浓度、使用2mL BaCrO_4进行交换反应、煮沸3min,得到方法相对标准偏差小于10%,加标回收率为92.9%～110%。实验结果表明,直接显色的测定方法灵敏、快速、准确度高。方法测定条件易于获得,适于推广应用。     

Templated Synthesis of Ordered Mesoporous Carbons with Tailored Structures and Morphologies

Due to the excellent biocompatibility and the capability to load and release drugs, ordered mesoporous carbons (OMCs) have been highly prospective and valuable in drug delivery system. In this contribution, synthesis of OMCs with tailored pore sizes from 4.1 to 3.4 nm was achieved by employing SBA‐15 as template and furfuryl alcohol (FA) as carbon precursors. An array of OMCs with controlled structures and morphologies by incipient wetness with FA was analyzed by powder X‐ray diffraction (XRD), nitrogen adsorption, transmission electron microscopy (TEM), and Raman spectroscopy. The resulting carbon replicas retained the hexagonal symmetry of the silica templates SBA‐15 with p6mm space group, although the framework suffered shrinkage in the replicated process. The pore size distribution, uniformity and pore volume of the mesopores in the OMCs were affected by structural properties of the SBA‐15 templates as shown by N₂ sorption and XRD pattern analysis. The process had the advantage that the textural parameters of the obtained OMCs were tunable simply by varying aging temperature of the silica template and the ratio of carbon precursor.     

A comprehensive study for selective removal of Cr(VI) by asymmetric imidazolium bromide salts as environmentally-friendly extractant

The study was to determine selective removal and recovery of Cr(VI) from acidic media by solvent extraction (SX) using asymmetric imidazolium-based room temperature imidazolium bromide salts (ARTILs) as the extractants. The relevant parameters on the extraction and the stripping of Cr(VI) were investigated to identify optimum conditions. The optimum conditions were determined as equilibration time 5 minutes, acid concentration and type 0.5?mol/L H₂SO₄, stirring speed 1200?rpm, extractant concentration and type 0.5?mol/L ARTIL5, phase ratio 2.0 and stripping reagent type, and concentration 2.0?mol/L NH₃. In optimum conditions, decyl substituted ARTIL was best in extraction process about 99.7% of extraction rate, whereas moderately hydrophobic pentyl substituted ARTIL was best in stripping process about 70.0% of stripping rate. Also, the optimized process was found as so selective toward Cr(VI) in the presence of the other metal ions with an environmental-friendly liquid–liquid–based SX method.     

新型荧光碳点的制备及其在Hg2+检测中的应用

以中药材川佛手为碳源,通过高温热解产生的烟制备了平均粒径为6 nm的新型荧光碳点,其最大激发波长285 nm,最大荧光发射波长340 nm。 基于碳点良好的荧光性能及Hg²⁺对碳点荧光的猝灭作用,建立了检测Hg²⁺的新方法。 结果表明,在0.2 mol/L磷酸盐缓冲溶液(pH=7.0)中,响应时间为2 min时,该方法具有良好的选择性和抗干扰能力,检测Hg²⁺浓度的线性范围为0.2~40 μmol/L,相关系数为r=0.9996,检出限为0.052 μmol/L。 当加入2.0和40.0 μmol/L Hg²⁺到实际水样后,相对标准偏差(RSD)和加标回收率分别为0.3%~2.4%和99.5%~101.1%,可用于实际水样中Hg²⁺的分析检测。     

姜黄中姜黄素的提取及电化学测定

姜黄中大约含有1%～3%的姜黄素,用95%乙醇从姜黄中浸取姜黄素,超声场介入下浸取的浸取速率最快.在0.2 mol/L磷酸盐缓冲溶液中（pH3.3）,姜黄素于玻碳电极上存在可逆的单电子转移过程,据此本实验首次建立了以线性扫描溶出伏安法检测姜黄素含量的新方法.在-0.2 V（vs SCE：饱和甘汞参比电极）电位下,含姜黄素的电解液于玻碳电极上经过富集,可得到一灵敏的氧化峰,峰电位Epa为＋0.464 V.在最佳条件下,氧化峰峰电流Ip与姜黄素浓度在8.0×10^-9～4.0×10^-7mol/L范围内呈线性关系,最低检出限为2.0×10^-9mol/L.本法操作简单、快速、灵敏、准确,可用于药物中姜黄素含量的直接测定.     

氯化稀土催化ε-己内酯开环聚合

Ring-opening polymerization of ε-caprolactone catalyzed by rare earth chloride dissolved in N,N-dimethylformamide and adding a small amount of propylene oxide was studied.The optimum conditions for the ring-opening polymerization of CL are as follows.In the bulk polymerization: n(DMF)/n(LaCl₃)=10,n(PO)/n(LaCl₃)=20,aging temperature: 30 ℃,aging time: 1 h,c(CL)=7.91×10^-3 mol/L,c(LaCl₃)=1.58×10^-5 mol/L,the polymerization carried out at 30 ℃ for 1 h,yield=83.3%,M_ν=1.93×10⁴.In the solution polymerization: n(DMF)/n(LaCl₃)=10,n(PO)/n(LaCl₃)=20,aging temperature: 30 ℃,aging time: 1 h,toluene as the solvent,c(CL)=4.22×10^-3 mol/L,c(LaCl₃)=8.43×10^-6 mol/L,the polymerization was carried out at 30 ℃ for 2 h,yield=62.9%,M_ν=1.21×10⁴.     

Self-catalyzed synthesis of mesoporous carbons with tunable pore size and structure by soft-templating method

A series of mesoporous carbons (MCs) have been obtained through organic–organic self-assembly method by using phloroglucinol–formaldehyde as carbon precursor and a reverse amphiphilic triblock copolymer as a template. Because of its acidity, the phloroglucinol was used as a catalyst itself. Results show that the pore size and structure of MCs were tailored by simply tuning the weight content of formaldehyde while keeping other reactants constant. A cylindrical mesostructure was obtained when the weight content was 1.0, 1.2 and 1.4. Further increasing the weight content to 1.6 or 2.0, a three-dimensional cage-like mesostructure was obtained. Specific surface area and pore volume up to 485 m²/g and 0.78 cm³/g can be reached, respectively. In addition, the pore size can be tuned in the range of 4.9–14.8 nm by changing the content of formaldehyde.     

Organic acid-assisted soft-templating synthesis of ordered mesoporous carbons

A series of soft-templated ordered mesoporous carbons (OMCs) was synthesized by using resorcinol and formaldehyde as carbon precursors, triblock copolymer Pluronic F127 as a soft-template, and an organic acid (acetic, benzoic, citric, oxalic, or succinic) as a polymerization reaction catalyst. The aforementioned organic acids were strong enough to facilitate the formation of ordered mesophases by the block copolymer template used and to catalyze the polymerization reaction of resorcinol and formaldehyde in this template. The use of weak organic acids instead of strong inorganic acids such as HCl eliminated inorganic anions from the reaction environment and resulted in high surface area OMCs. Basically, the resulting carbons showed the surface areas and pore volumes comparable to those reported for the carbons prepared under similar conditions but in the presence of strong inorganic acids. Electron microscopy analysis proved the presence of ordered mesopores, whereas thermogravimetric analysis showed a good thermal stability of these carbons.     

Extraction of gadolinium from El-Garra El-Hamra rare-earth cake,South Western Desert,Egypt

The study area of El-Garra El-Hamra is one of the igneous masses located in the southern part of the Western Desert of Egypt. This work has been carried out to investigate the process of gadolinium separation from REEs cake obtained from El-Garra El-Hamra ore concentrate. It is considered as a new approach in the Nuclear Materials Authority of Egypt. Firstly; the optimum leaching conditions achieved are 200 gm/L H₂SO₄, 1/2 solid/liquid ratio, 4 h agitation time,?125 mesh size and at 90 ^°C temperature. Then by solvent extraction method using 1 mol/L D2EHPA middle REEs were extracted. The organic extractant was stripped by using 2 mol/L HCl and Gd pregnant solution was obtained. Then, the relevant optimum factors were 0.3 mol/L D2EHPA diluted by kerosene, 10 min contact time, and 4/1 organic/aqueous ratio giving 87 % Gd extraction. Then, the scrubbing of the loaded extractant was by 1 mol/L HCL followed by Gd stripping using 5 M HCl, contact time of 30 min and 1/3 organic/aqueous ratio. The strip solution was subjected to evaporation and little amount was dried to obtain GdCl₃ powder having a purity of about 81 % associated with YCl₃ 4 %.     

Monitoring human serum transferrin by capillary zone electrophoresis with end-column amperometric detection

Capillary zone electrophoresis was employed for the determination of human serum transferrin using end-column amperometric detection with a carbon fiber microelectrode at a constant potential of 1.9 V vs. saturated calomel electrode (SCE). The optimum conditions of separation and detection are 7.5 x 10(-4) mol/L Tris-3.44 x 10(-4) mol/L HCl for the buffer solution, 20 kV for the separation voltage, 5 kV and 10 s for the injection voltage and the injection time, respectively. The limit of detection is 6.7 x 10(-8) mol/L or 440 amol (S/N = 2). The relative standard deviations are 0.67% for the migration time and 1.5% for the electrophoretic peak current. The method was applied to the determination of transferrin in human serum. The recovery is between 93-104%.     

氯化铝中萃取铁工艺

采用萃取剂N,N,N',N'-四丁基丙二酰胺(TBMA) 、N,N,N',N'-四辛基-3-氧戊二酰胺(TODGA)和甲基异丁基甲酮(MIBK)从氯化铝水溶液中萃取铁,以制备高纯氯化铝。 研究结果表明,当氯化铝溶液中盐酸浓度在4 mol/L左右时,TBMA和MIBK的萃取率在90%以上。 TODGA显示出优异的萃取分离性能。 当氯化铝溶液中Al³⁺浓度为2.0 mol/L,Fe³⁺浓度为0.0036 mol/L(0.2 g/L),HCl浓度为1.2 mol/L时,0.20 mol/L TODGA的环己烷或环己烷有机相对铁的一次萃取率达到99.9%以上,多次萃取后溶液中的铁含量低于0.01 mg/L,能深度去除氯化铝中的铁杂质,在工业化生产中有极大的应用价值。     

Validated method for the determination of carboplatin in biological fluids by Zeeman atomic absorption spectrometry

We have developed and validated a rapid, simple and sensitive analytical method, based on Zeeman atomic absorption spectrometry, for the quantitative analysis of carboplatin in human plasma, plasma-ultrafiltrate (UF), saliva and urine. The sample pretreatment is simple and only involves dilution of the samples with a solution containing 0.15 mol/L NaCl and 0.2 mol/L HCl in water (diluent). The caroplatin concentrations in the different biological matrices could be quantified using a standard curve constructed in plasma UF: diluent (1:10; v/v). The validated range of determination was 0.24 to 242 mol/L of carboplatin in plasma UF, 0.84 to 242 mol/L in plasma, 0.12 to 3.64 mol/L in saliva, and 2.02 mol/L to 12.1 mmol/L in urine. Matrix-effects were not observed. The stability of carboplatin (determined as Pt) in biological samples stored at –20°C was checked for a period of 8 months; no losses occurred during this period. The performance of the method, in terms of accuracy and precision, fitted well within the generally accepted criteria for validation of analytical methodologies. The proposed method was utilized in a pharmacokinetic study in one patient to demonstrate the usefulness of the assay.     

席夫碱缓蚀剂的合成及其对碳钢材料缓蚀性能

采用失重法和电化学方法研究了2种席夫碱类缓蚀剂N,N′-二水杨醛基-1,2-乙二亚胺（SB-Ⅰ）和水杨醛基吡啶-2-亚胺(SB-Ⅱ)在1 mol/L盐酸溶液中对A3碳钢的缓蚀性能。 失重实验表明,SB-Ⅰ和SB-Ⅱ在1 mol/L盐酸溶液中的浓度为20 mmol/L时,缓蚀效率分别达85%和92%。 经三电极体系极化曲线和交流阻抗谱测定实验表明,缓蚀性能是由于碳钢材料表面为缓蚀剂分子吸附所致,二者均属阴极型缓蚀剂。     

Determination of clozapine by capillary zone electrophoresis following end-column amperometric detection with simplified capillary/electrode alignment

Capillary zone electrophoresis was employed for the determination of clozapine using an end-column amperometric detection at a carbon fiber array microdisk electrode with simplified capillary/electrode alignment. The optimum conditions of separation and detection are: Britton-Robinson buffer, pH 2.0 (1.3 x 10(-2) mol/L total concentration of acids, 3.2 x 10(-3) mol/L NaOH), 15 kV for separation voltage, 5 kV and 10 s for injection voltage and injection time, respectively. The limit of detection is 4.2 x 10(-7) mol/L or 1.2 fmole (signal to noise, S/N = 2). The relative standard deviation is 1.4% for the migration time and 2.5% for the electrophoretic peak current. The method was applied to the determination of clozapine in human blood. The recovery of the method is between 94-104%.     

聚苯胺/钴-氧化钴膜作传感元件的pH传感器的性能

本文研究了在玻碳电极上修饰不同物质所制得的pH传感器,通过电位滴定的方法比较得出先修饰聚苯胺,再修饰钴-氧化钴膜的电极对pH有较好的响应,能代替玻璃电极应用在实际样品测定中。探究了最佳修饰条件为：先在0.1mol/L苯胺的盐酸（1mol/L）溶液中, 电位范围为-0.2~1.0V,以100 mV/s 的扫描速度循环伏安扫描 10圈修饰聚苯胺膜;接着在含2.0×10-4 mol/LCo2+的PBS （pH=7.5）缓冲溶液中, 电位范围为-1.2~1.2V,以100 mV/s 的扫描速度循环伏安扫描 5圈修饰钴-氧化钴膜。得到的修饰电极响应斜率为-61.60 mV/pH,响应范围pH 0.5~13。     

高效液相色谱-电化学检测法测定鼠脑微透析液中谷胱甘肽和半胱氨酸

采用高效液相色谱法,用电化学检测手段成功地测定了沙土鼠脑纹状体微透析液内的谷胱甘肽（ＧＳＨ）和半胱氨酸（Ｃｙｓ）。检测前用电化学自清洗方式能有效地提高玻璃碳电极的检测水平,使其具有较好的重现性和回收率。Ｃｙｓ和ＧＳＨ的回收率分别为９１．４％和８７．３％。电化学检测的工作电压为０．９Ｖ,用外标法定量。由微透析探针获取的纹状体透析液Ｃｙｓ和ＧＳＨ的浓度分别为６８．５９和６５．５４ｎｍｏｌ／Ｌ,验证了方法的实用性和可靠性。