溶出伏安法对维生素K3的研究与测定

应用微分脉冲溶出伏安法(DPSV)对维生素K3在玻碳电极(GCE)上的电化学行为进行了研究.在氨水-NH4Cl(pH 9.0)底液中,对维生素K3进行循环伏安扫描,发现有一对良好的氧化还原峰出现,对电极反应机理进行了探讨.阴极溶出伏安峰电流与其浓度在2.0×10-6～1.0×10-4mol·L-1范围内呈线性关系(r=0.998 5),检出限为4.0×10-7mol·L-1.对于1.0×10-5mol·L-1的维生素K3,平行7次测定结果的RSD为1.15%.应用此方法对亚硫酸氢钠甲萘醌注射液进行了测定,方法的回收率为97.3%～102.5%.     

线性扫描极谱法测定微量肉桂酸

在 1mol·L-1HOAc NaOAc介质中 (pH =3.6 ) ,肉桂酸有一还原峰 ,其峰电位为 - 1.4 7V(vs.SCE)。峰电流与肉桂酸浓度在 2 .0× 10 -5～ 8.0× 10 -4 mol·L-1之间呈线性关系 (r =0 .9989) ,检出限为 1.0× 10 -5mol·L-1。该法应用于肉桂酸含量的测定 ,结果满意 ,并对肉桂酸的电化学性质进行了研究     

酪氨酸基于表面活性效应在碳糊电极上的伏安行为研究

研究了酪氨酸在表面活性剂存在下于碳糊电极上的电化学行为,发现表面活性剂能显著提高酪氨酸的氧化电流,在此基础上,建立了一种直接测定酪氨酸的电化学方法。优化了测定酪氨酸的试验参数,即介质的pH、扫描速度、富集电位和富集时间、表面活性剂的种类及其浓度等。峰电流与酪氨酸在1×10-7～3×10-5mol·L-1浓度范围内呈良好的线性关系,检出限为6×10-8mol·L-1。1×10-5mol·L-1酪氨酸平行测定8次的标准偏差为4.6%。用该方法测定了人体尿液中酪氨酸的含量,取得了满意的结果。     

丝网印刷普鲁士蓝修饰电极催化还原测定过氧化氢

制备了普鲁士蓝修饰的丝网印刷过氧化氢传感器,研究了过氧化氢在该修饰电极上的电催化还原特性,考察了有关修饰膜制备和试验条件对传感器性能的影响。结果表明,pH4.0的0.2mol·L-1KH2PO4 K2HPO4缓冲溶液(PBS)中,修饰电极对过氧化氢显示出快速的电化学响应,较高的稳定性、重现性和催化活性,测定的线性范围为1.0×10-5～1.0×10-3mol·L-1,相关系数为0.999,检出限为6.0×10-6mol·L-1(3σ)。电极制作方法简便,可用于实际样品的测定。     

催化氢波-单扫描示波极谱法测定克拉霉素

建立一种灵敏快速测定克拉霉素的新方法。在 0. 24 mol·L-1 KH2PO4 Na2HPO4(pH 6.81)支持电解质中,克拉霉素于-1.57 V(vs.SCE)处产生一催化氢波,其二阶导数峰峰电流与克拉霉素浓度在2.0×10-6~ 1.6×10-4mol·L-1范围内呈线性关系(r=0.999 4,n=8),检出限为1.0×10-6 mol·L-1。10 次测定 1. 0×10-5 mol·L-1 克拉霉素峰电流相对标准偏差为1 8%,回收率在98.3%~100.6%之间。该方法可用于药剂中克拉霉素的测定。     

L-半胱氨酸自组装膜修饰电极对对氨基酚电催化氧化及其分析应用

在裸金电极上制备了L 半胱氨酸自组装膜修饰电极(L Cys/AuSAMs),研究了对氨基酚(p AP)在L Cys/AuSAMs上的电化学行为,发现该膜电极对p AP的氧化具有良好的电催化作用。氧化峰电位降低了128mV,测得p AP的扩散系数D为1.27×10-6cm2·s-1,初步探讨了电催化机理。采用水平衰减全反射 傅立叶变换红外光谱(ATR FTIR)技术对L Cys/AuSAMs进行了表征;方波伏安法(SquareWaveVoltammetry,SWV)测定p AP,其氧化峰峰电流与p AP浓度在1.0×10-8～8.0×10-8mol·L-1和1.0×10-7～2.0×10-4mol·L-1范围内呈线性关系,相关系数分别为0.9978和0.9977,检出限为2.0×10-9mol·L-1。该电极用于模拟废水样的测定,结果满意。     

普鲁士兰修饰碳黑微电极同时微分伏安法测定多巴胺和抗坏血酸

将含有1.0%普鲁士蓝的碳黑与固体石蜡按2.5∶1(质量比)混合后装入φ0.2mm的石英毛细管中,在其上端插入一铂丝并抛光后即制成普鲁士蓝修饰碳黑微电极.对多巴胺(DA)及抗坏血酸(VC)在此电极上的电化学行为及应用此电极测定两组分的最佳条件进行了研究,在定量测定中采用二次微分线性扫描伏安法.在最佳条件下,DA与VC的峰电流(i″p)分别与各自的浓度保持如下线性关系DA为4.0×10-6～8.0×10-4mol·L-1,VC为6.0×10-5～1.0×10-3mol·L-1;检出限(3σ)依次为2.0×10-6mol·L-1及1.0×10-5mol·L-1.应用此方法分析了3种含DA及VC的混合溶液,测得结果的相对标准偏差(n=8)依次小于2.0%及3.0%,回收率范围依次为96.5%～101.0%及95.0%～102.5%.     

聚荧光素薄膜修饰电极对多巴胺的电催化作用

利用聚荧光素薄膜修饰电极对多巴胺(DA)的电催化作用,建立了一种定量检测痕量多巴胺的方法。试验结果表明,DA的浓度在5．27×10-6～2．03×10-4mol·L-1范围内,氧化峰电流与浓度呈良好的线性关系,检出限可达2．1×10-7mol·L-1。用于盐酸多巴胺针剂样品的测定, 8次测定结果的相对标准偏差为2．5％,样品回收率为100．1%。     

CTAB化学吸附修饰电极线性扫描伏安法直接测定苯酚

本文提出了以十六烷基三甲基溴化铵(CTAB)修饰碳糊电极直接测定苯酚的电化学方法。在pH=8.0的0.1mol·L-1磷酸盐缓冲溶液中,苯酚在+0.63V出现一个灵敏的氧化峰,其峰电流与苯酚浓度在4.0×10-7～5.0×10-5mol·L-1之间呈线性关系,检出限为5.0×10-8mol·L-1。本文对CTAB对苯酚氧化的增敏机理进行了探讨。该电极用于工业废水中苯酚的检测,取得了满意的结果。     

多糖激活的酪氨酸酶生物电极测定酚类的研究

研制了以麦芽糊精作为酪氨酸酶的激活剂 ,采用Nafion117膜抗阴离子干扰 ,聚乙烯亚胺 (PEI)作包埋剂以抗阳离子干扰的酪氨酸酶碳糊电极。工作电位为 - 10 0mV [vs.Hg/Hg2 Cl2(s) ],pH为 5 .4 0 ,测量时间为 1.0min。在此测量条件下 ,电极对苯酚的检出限为 5 .0× 10 - 8mol·L- 1,线性范围为 2 .0× 10 - 7～ 5 .0× 10 - 5mol·L- 1,RSD为 1.2 %。用所研制电极测定炼油废水中酚的含量 ,加标回收率为 10 0 .7%。     

The Colloidal Stabilization of Carbon with Carbon: Carbon Nanobubbles as both Dispersant and Glue for Carbon Nanotubes

The superior physical properties of carbon nanotubes (CNTs) have led to their broad application. Intrinsically, CNTs tend to agglomerate from hydrophobic interactions, which is highly undesirable for solution processing and device fabrication. Commonly, a stabilizer consisting of organic surfactants or polymers is used to disperse CNTs. Recently, we synthesized nitrogen‐doped carbon hollow nanospheres (25–90 nm), termed carbon “nanobubbles”. They bear superior dispersability in water and distinctive graphitic order. Herein, we describe the nanobubble‐assisted dispersion of CNTs in aqueous solution upon sonication. This process relies on the π–π interaction between the two aromatic carbon nanostructures, which can process their carbon mixture in water into conductive filter membranes, ink, and discs. This stabilization can be extended to other aromatic carbons. In addition, the π–π interaction may create a new type of carbon p–n junction that can be used to improve charge separation.     

一维新型碳的同素异形体:碳链

碳链是一种完全一维的、具有电子轨道sp杂化结构的新型碳的同素异形体.正是由于碳链的独特的一维结构,使其拥有区别于富勒烯、石墨烯和碳纳米管的化学键,从而表现出更加优异的性能,如:理论预言碳链的机械强度是石墨烯的几倍;碳链的导热也类似于石墨烯和碳纳米管;碳链是具有直接带隙的半导体材料,且带隙的大小可以通过其长度来调控,其长...     

Adsorption of Carbon Dioxide on Activated Carbon

The adsorption of CO2 on a raw activated carbon A and three modified activated carbon samples B, C, and D at temperatures ranging from 303 to 333 K and the thermodynamics of adsorption have been investigated using a vacuum adsorption apparatus in order to obtain more information about the effect of CO2 on removal of organic sulfur-containing compounds in industrial gases. The active ingredients impregnated in the carbon samples show significant influence on the adsorption for CO2 and its volumes adsorbed on modified carbon samples B, C, and D are all larger than that on the raw carbon sample A. On the other hand, the physical parameters such as surface area, pore volume, and micropore volume of carbon samples show no influence on the adsorbed amount of CO2. The Dubinin-Radushkevich (D-R) equation was the best model for fitting the adsorption data on carbon samples A and B, while the Preundlich equation was the best fit for the adsorption on carbon samples C and D. The isosteric heats of adsorption on carbon samples A, B, C, and D derived from the adsorption isotherms using the Clapeyron equation decreased slightly increasing surface loading. The heat of adsorption lay between 10.5 and 28.4 kJ/mol, with the carbon sample D having the highest value at all surface coverages that were studied. The observed entropy change associated with the adsorption for the carbon samples A, B, and C (above the surface coverage of 7 ml/g) was lower than the theoretical value for mobile adsorption. However, it was higher than the theoretical value for mobile adsorption but lower than the theoretical value for localized adsorption for carbon sample D.     

Growth of Single-walled Carbon Nanotubes on Substrates Using Carbon Monoxide as Carbon Source

The growth of single-walled carbon nanotubes(SWCNTs) on substrates has attracted great interests because of the potential applications in various fields. Carbon monoxide(CO) was used as the carbon source for the growth of SWCNTs on silicon substrates. Random or oriented SWCNTs can be produced by varying the CO flow rate. When the flow rate of CO was as low as 20 sccm(sccm:standard cubic centimeter per minute), dense SWCNT networks with clean surface were produced. When the flow rate was above 50 sccm, vertically aligned SWCNT(VA-SWCNT) arrays were grown. Well-aligned VA-SWCNT arrays were obtained in the temperature range of 650-800℃ and the content of large-diameter(above 1.7 nm) tubes in the array increased with the temperature. The height of the array was affected by the growth temperature, the CO flow rate, and the growth time. These findings indicate CO can be used as an efficient carbon source for the growth of SWCNTs on substrates under low flow rates.     

埃洛石纳米管模板法一步法制备一维碳纳米管/碳纳米棒混合纳米碳材料

利用埃洛石纳米管(HNTs)特有的中空纳米结构,以及丰富的界面化学性质,以聚乙烯醇(PVA)为碳源,采用浸渍填充纳米孔方法实现了一步制备一维碳纳米管(CNTs)/碳纳米棒(CNRs)混合纳米碳材料。考察模板剂(HNTs)和碳源(PVA)之间的比例关系对混合纳米碳材料的结构影响,利用XRD、FTIR、Raman、N2吸附-脱附测试、TEM、SEM以及电阻率和分散性等表征手段分析混合纳米碳材料的结构变化。结果发现,PVA填充含量的增加将导致产物中CNRs的质量分数增加;当PVA和HNTs质量之比为1∶1时,所制备的CNTs/CNRs的孔体积达到最大值2.142 cm~3·g-1,比表面积达到583 m~2·g-1,并且表现出较好的电导率和分散性,表明低的PVA填充比例制备的混合碳材料中CNTs含量较高。     

Carbon clusters

Some of the most significant discoveries and achievements concerning the mass spectra and gas phase ion chemistry of carbon clusters are reviewed. These include (1) nanosecond and femtosecond laser ionizations; (2) ion structures through ion/molecule reactions, ion chromatography, and computational methods; (3) carbon cluster cooling through radiative decay, dissociative decay, and thermionic emission; (4) mechanisms and energetics of fragmentation reactions; (5) endohedral fullerenes including recent data on ion beam implantation, and (6) ion chemistry as a function of the fullerene charge state.     

二氧化碳与低碳经济发展

由于二氧化碳无色无味,又存在于大气中,因此它在植物生长中的重要性被人类忽略了。其实二氧化碳是光合作用的反应物,是植物生长的重要原料;又是一种新型绿色肥料。人类应该着力开发以二氧化碳为原料的新型肥料发展低碳经济。     

Ni/γ-Al2O3催化剂上CH4-CO2重整体系中积碳-消碳的研究

用动态热重技术和色谱技术联用以及XRD和TEM等表征手段,研究了Ni/γ-Al     

Palladium-Catalyzed Addition of Carbon Monoxide and Carbon Tetrachloride to 1-Octene in Supercritical Carbon Dioxide

The Pd-catalyzed addition of carbon monoxide and carbon tetrachloride to 1-octene gave coadduct [alkyl 2-( 2, 2, 2-trichloroethyl)octanoate] as the major product in supercritical carbon dioxide by using pyridine as the base. It was found that the selectivity and the yield of coadduct were greatly affected by the pressure of carbon dioxide, the reaction temperature and the amounts of alcohol and base used.     

碳纳米管含量对炭炭复合材料组织及力学性能的影响

炭纤维上原位合成了均匀生长且具有伸张形貌的碳纳米管,借助化学气相渗透制备了碳纳米管增强的炭炭复合材料,研究了不同含量的碳纳米管对炭炭复合材料组织和力学性能的影响。结果表明：炭纤维上生长碳纳米管改变了热解炭的沉积行为,诱导了各向同性热解炭的生成,且随着碳纳米管含量的增加,各向同性热解炭的厚度增加,但是复合材料的d002值却明显降低。微量的碳纳米管即可显著提高复合材料的力学强度,随着其含量的增加,复合材料的力学强度和模量迅速提高,但材料的断裂行为却急剧恶化,断裂模式由最初的假塑性断裂转变为脆性断裂。