芦丁在纳米金修饰玻碳电极上的电化学行为及其测定

采用循环伏安法将纳米金电沉积于玻碳电极表面,制备了纳米金修饰玻碳电极(NG/GCE).在pH3.29的Britton-Robinson(B-R)缓冲溶液中,用循环伏安法研究了芦丁在NG/GCE上的电化学行为.结果表明,NG/GCE对芦丁的氧化还原反应有良好的电催化作用.用方波伏安法测得芦丁的还原峰电流与其浓度在2.0×10-8～2.0×10-6mol/L范围内呈线性关系,检出限为1.0×10-8mol/L(S/N=3).     

聚L-半胱氨酸/还原氧化石墨烯/Nafion修饰玻碳电极对芦丁的电化学传感行为研究

本文采用滴涂法制备了还原氧化石墨烯/Nafion溶液修饰玻碳电极(rGO/Nafion/GCE),用电化学聚合法将L-半胱氨酸(L-Cys)聚合在rGO/Nafion/GCE表面,得到Poly-L-Cys/rGO/Nafion/GCE。采用伏安法研究了芦丁在该修饰电极上的电化学行为及其影响因素。结果表明,L-Cys的电聚合圈数对修饰电极的电化学性能具有一定的影响。在最优条件下,芦丁的峰电流与其浓度在2.0×10~(-8)~1.0×10~(-5) mol/L内呈现好的线性关系,检出限(S/N=3)为1.0×10~(-8) mol/L。     

聚(三聚氰胺)与金纳米粒共修饰玻碳电极用于芦丁的电化学测定

通过电聚合和电沉积方法首次制得聚(三聚氰胺)和金纳米粒共修饰的电极(PMel/Au/GCE),并对修饰电极进行交流阻抗电化学分析。采用循环伏安法研究了芦丁在修饰电极上的电化学行为,发现其氧化峰电流和还原峰电流较裸玻碳电极(GCE)以及聚(三聚氰胺)修饰的电极(PMel/GCE)明显增强,提高了检测的灵敏度。对溶液的pH值、金纳米粒子电沉积时间、三聚氰胺电聚合时间和扫描速率等实验条件进行了优化。采用示差脉冲伏安法对芦丁进行定量分析,芦丁浓度分别在7.8×10-9~1.2×10-6mol/L和1.2×10-6~1.5×10-5mol/L范围内与峰电流呈线性,其相关系数(r2)分别为0.997和0.993,检出限(S/N=3)为5.5×10-9mol/L。将该电极用于市售芦丁片检测,回收率为96.4%~101.8%。     

芦丁在铂纳米/碳纳米管修饰电极上电化学行为研究

通过电沉积的方式在多壁碳纳米管(MWCNTs)修饰玻碳电极表面上沉积铂(pt)纳米粒子,并运用循环伏安法(CV)、示差脉冲伏安法(DPV)探讨了芦丁在铂纳米/碳纳米管/玻碳电极上的电化学行为.实验结果表明,芦丁在该修饰电极上呈现一对良好氧化还原峰,其氧化峰电流与浓度在3.2×10(-8)～1.2×10(-5)mol/L...     

壳聚糖/多壁碳纳米管复合膜电化学手性识别色氨酸对映异构体

采用滴涂方式将羧酸化多壁碳纳米管(f-MWCNTs)修饰于玻碳电极(GCE)表面成膜,然后恒电位法在上述修饰电极表面电沉积壳聚糖(CS)膜,形成CS和f-MWCNTs复合膜修饰电极(CS/f-MWCNTs/GCE),并用于色氨酸(Trp)对映异构体的手性识别。采用扫描电子显微镜(SEM)表征了修饰电极表面形貌的差异,电化学阻抗(EIS)和循环伏安法(CV)研究修饰电极的电化学行为差异。差分脉冲伏安法(DPV)用于区别色氨酸(Trp)对映异构体,分离系数可达2.38。研究发现该修饰电极对L-Trp的DPV响应信号强于D-Trp,检测的线性范围为8.0×10~(-6)~4.0×10~(-3)mol/L,检出限(S/N=3)为5.0×10~(-6)mol/L。该方法简单、经济、快速,对发展其它手性化合物的检测方法提供了参考。     

聚L-白氨酸-碳纳米管修饰电极同时检测对苯二酚和邻苯二酚

用Nafion将单壁碳纳米管(SWCNT)固定到玻碳电极(GCE)上,再利用电化学聚合方法将L-白氨酸(L-LEU)聚合到SWCNT/GCE上,制备得到poly L-LEU/SWCNT/GCE修饰电极。采用循环伏安法(CV)、差分脉冲伏安法(DPV)和电化学交流阻抗法(EIS)研究了对苯二酚(HQ)、邻苯二酚(CC)共存时,二者在修饰电极上的电化学行为。结果表明:此修饰电极对HQ和CC有很好的电催化和分离作用。二者在修饰电极上的氧化还原峰电流与GCE相比显著增强,HQ和CC的氧化峰电位差和还原峰电位差分别为124 mV和131 mV。HQ和CC的检测线性范围分别为2.0×10-7~1.0×10-4、5.0×10-7~1.0×10-4mol/L。检出限分别为8.0×10-8、1.0×10-7mol/L。制备的修饰电极重现性、稳定性良好。在模拟废水中采用该修饰电极对HQ和CC进行检测,结果满意。     

纳米金/三聚氰胺修饰电极检测亚硝酸盐

采用电聚合方法制备三聚氰胺(MA)膜修饰玻碳电极(GCE),然后采用原位恒电位沉积法制备金纳米颗粒(Au),并将其修饰于膜电极表面,制得纳米金/三聚氰胺修饰玻碳电极(Au/MA/GCE)。用扫描电子显微镜(SEM)对修饰电极进行表面形貌和元素成分分析。用循环伏安法研究亚硝酸根(NO2-)在该修饰电极上的电化学行为发现,NO2-在0.85 V出现一灵敏的氧化峰。在优化的实验条件下,NO2-在1.0×10-5～1.0×10-3mol/L浓度范围内与其氧化峰电流成线性关系,检测下限为8.9×10-7mol/L。将修饰电极用于实际样品中NO2-的检测,效果良好。     

纳米金/石墨烯复合膜修饰电极检测异烟肼EI北大核心CSCD

先采用滴涂法制备了石墨烯修饰电极(GR/GCE),然后采用电化学方法将纳米金沉积于石墨烯表面制备了纳米金/石墨烯复合材料修饰电极(Au NPs/GR/GCE)。研究了异烟肼(isoniazid,INZ)在该Au NPs/GR/GCE上的电化学行为。结果表明,异烟肼在该修饰电极上有良好的电化学响应。在优化条件下,线性扫描伏安法测定异烟肼的线性范围为1.0×10-7~1.0×10-4mol/L,检出限为5.0×10-8mol/L(S/N=3)。用该法测定了异烟肼注射液中异烟肼的含量,结果令人满意。     

电沉积法制备铁氰化铈/Nafion复合物纳米颗粒及其对多巴胺电催化氧化性能的研究

采用电沉积法沉积铁氰化铈(CeHCF)纳米颗粒,在Nafion修饰的玻碳电极表面电沉积致密的、分散性良好的铁氰化铈纳米粒子。用场发射扫描电子显微镜(FE-SEM)对铁氰化铈纳米颗粒的形貌进行了表征。利用循环伏安法(CV)研究了多巴胺在铁氰化铈/Nafion修饰玻碳电极(CeHCF/NF/GCE)表面上的电化学行为。研究表明,CeHCF/NF/GCE对多巴胺具有良好的电催化氧化作用,该传感器对多巴胺在一定浓度下呈良好的线性关系,其线性范围是1.0×10~(-7)~3.4×10~(-4)mol/L。检测限为0.2×10~(-7)mol/L(S/N=3)。     

纳米金/石墨烯复合膜修饰电极检测异烟肼

先采用滴涂法制备了石墨烯修饰电极(GR/GCE),然后采用电化学方法将纳米金沉积于石墨烯表面制备了纳米金/石墨烯复合材料修饰电极(Au NPs/GR/GCE)。研究了异烟肼(isoniazid,INZ)在该Au NPs/GR/GCE上的电化学行为。结果表明,异烟肼在该修饰电极上有良好的电化学响应。在优化条件下,线性扫描伏安法测定异烟肼的线性范围为1.0×10-7~1.0×10-4mol/L,检出限为5.0×10-8mol/L(S/N=3)。用该法测定了异烟肼注射液中异烟肼的含量,结果令人满意。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

解决能源问题的新途径--光解水制氢的研究

面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。