一种提高双氢青蒿素电化学检测分辨率的新方法

采用电化学方法研究了阳离子表面活性剂对双氢青蒿素(DHA)在银电极表面伏安行为的影响,并探讨了其电极界面的电化学机理。随着阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)的加入,DHA的还原峰电位发生明显的变化。当CTMAB的浓度为1.0×10-5mol/L时,DHA的峰电位正移了102 mV,活化能降低,DHA的过氧键更容易断裂。当CTMAB的浓度继续增大至7.0×10-4mol/L,DHA的峰电位负移了108 mV,活化能增大,DHA的过氧键更稳定。同时,还研究了酸度、温度和不同结构的阳离子表面活性剂对DHA伏安行为的影响,并提出其作用机制,从而建立一种提高DHA电化学检测分辨率的新方法。     

青蒿素与L-半胱氨酸的作用研究

研究了青蒿素与L-半胱氨酸的相互作用.循环伏安实验表明,在20%乙醇(v/v)+B-R(Britton-Robinson)缓中溶液中(pH 7.2),青蒿素浓度为1.0×10-3 mol/L,L-半胱氨酸浓度≥2.0×10-5 mol/L时,在此二元混合溶液体系中形成了青蒿素-L-半胱氨酸二元加合物,该加合物在-1.03V电位下还原,并用紫外及红外光谱对加合物进行辅助表征,对二元加合物的形成机理进行了探讨.     

铜(Ⅱ)诱导双氢青蒿素过氧键断裂的电催化作用

双氢青蒿素(DHA)的过氧键是抗疟抗肿瘤作用的关键部位,过氧键的催化断裂将影响其药物活性.采用电化学方法研究了EDTA-Cu(Ⅱ)催化DHA过氧键的断裂,考察了酸度和扫描速率对体系的影响,并探讨了其催化作用的电极反应机理.结果表明,在含20%乙醇的B-R缓冲溶液(pH=7.2)中,一定浓度的EDTA-Cu(Ⅱ)使DHA于-0.681 V(vs SCE)处的还原峰峰电流上升,峰电位正移,表现出明显的电催化还原特征.当EDTA-Cu(Ⅱ)浓度为5.0×10-6mol/L,DHA浓度为5.0×10-4mol/L时,DHA的还原过电位降低了94 mV.与相同浓度的EDTA-Fe(Ⅲ)和血红素相比,EDTA-Cu(Ⅱ)具有更明显的催化效果,能催化DHA过氧键断键,从而影响DHA的药理活性.     

阿霉素在氧化铟锡电极上的电化学行为及其应用

阿霉素(ADM)在0.02 mol/L pH 7.50的NaH2PO4-Na2HPO4缓冲溶液中,用氧化铟锡(ITO)电极进行线性扫描伏安法测定,得到一良好的还原峰,其峰电位为-0.63 V。峰电流与ADM浓度在1.0×10-7~5.0×10-6mol/L范围内呈线性关系,检出限为5.0×10-8mol/L。用循环伏安法研究了体系的电化学行为及电极反应机理。实验表明,该体系属两电子还原的不可逆过程。     

纳米银/石墨烯修饰电极测定青蒿素

本文建立一种新型的青蒿素传感器。首先,在玻碳电极上滴涂氧化石墨,通过电化学方法将氧化石墨还原为石墨烯,然后,在石墨烯上沉积纳米银得到石墨烯/纳米银修饰电极,它作为检测青蒿素的电化学传感器。用此电极对青蒿素进行测定,并通过循环伏安法、差分脉冲伏安法、交流阻抗法等研究其电化学行为。该修饰电极在测定青蒿素溶液时,表现出较正的还原电位和较大的峰电流等优势;对其实验条件如电解质溶液的p H、应用电势等进行了探查,该电化学传感器在青蒿素溶液浓度范围为1.0×10-8~3.0×10-5mol/L时与其还原峰电流呈现良好的线性关系,最低检出限为1.2×10-9mol/L(S/N=3)。此外,对该传感器的稳定性和重现性等也进行了研究,获得令人满意的结果。     

硫唑嘌呤在聚合L-丝氨酸修饰玻碳电极上的电化学行为及其测定

本文研究了硫唑嘌呤在聚L-丝氨酸修饰电极上的电化学行为。在pH 6.0的磷酸盐缓冲溶液中,硫唑嘌呤在该修饰电极上呈现2个还原峰和1个氧化峰,其峰电位都随着pH值的增加而负移。采用线性扫描伏安法测定硫唑嘌呤,对于Ep=-0.65 V处还原峰,峰电流与其浓度在1.0×10-7~5.0×10-5mol/L范围呈良好的线性关系,其线性回归方程为ip(μA)=0.9632 0.8371c(μmol/L),检出限为1.0×10-8mol/L。该方法用于尿样中硫唑嘌呤的测定,结果满意。     

碱性品红共振散射法测定阴离子表面活性剂

在pH 6.0 Walpole缓冲溶液中,碱性品红(FB)与阴离子表面活性剂十二烷基苯磺酸钠(SDBS)在静电引力作用和疏水作用力共同作用下形成了紫红色离子缔合微粒,其分别在258、316、358和623nm处产生4个共振散射峰,最强峰位于316nm处。于优化实验条件下,在1.0×10-7～5.6×10-5mol/L范围内,体系的共振散射信号与SDBS浓度之间呈良好的线性关系,其检出限为1.86×10-12mol/L。该方法直接用于测定生活废水中的阴离子表面活性剂含量,得到较满意的结果,回收率为96.8%～106.9%。     

对硫磷在纳米氧化铝薄膜修饰电极上的电化学行为及其测定

制备了纳米氧化铝修饰玻碳电极(nano-Al2O3/GCE/CME),用循环伏安法(CV)、线性扫描伏安法(LSV)研究了对硫磷(TP)在nano-Al2O3/GCE/CME上的电化学行为.实验表明,该修饰电极与裸电极相比能显著提高TP的氧化还原峰电流并降低其氧化峰电位.在0.1 mol/L HAc-NaAc缓冲溶液(pH =5)中,TP在该修饰电极上产生1个不可逆的还原峰( Epc1=-0.567 V)和1对可逆氧化还原峰( Epa2=0.018 V和Epc2=-0.008 V) ,氧化峰电流与TP的浓度在2.5×10-9～1.0×10-7 mol/L和1.0×10-7～1.0×10-5 mol/L范围内具有良好的线性关系,回归方程分别为: ip(μA)=0.2529+4.201C(μmol/L), r=0.9984和ip(μA)=0.6752+0.3181C(μmol/L), r=0.9946.开路富集30 s后,检出限为1.0 ×10-9 mol/L(S/N=3).在1.0×10-5 mol/L TP试液中连续测定10次,其RSD为3.8%.用此方法测定了蔬菜中TP的含量,回收率为95. 6%～100.5% ,结果满意.     

对硫磷在聚乙烯吡咯烷酮修饰碳糊电极上的电化学行为及其分析研究

研究了对硫磷在聚乙烯吡咯烷酮(PVP)修饰碳糊电极(CPE)上的电化学行为,发现PVP能显著提高对硫磷的氧化还原峰电流.据此建立了一种直接测定对硫磷的电分析方法.对硫磷氧化峰电流与其浓度在2.5×10-8～1.0×10-6mol/L及1.0×10-6～1.0 × 10-5mol/L 范围内呈良好的线性关系,开路富集5 min后,检出限为7.5×10-9mol/L.在1.0×10-5mol/L的对硫磷试液中连续测定10次,其RSD为2.8%.用此方法测定了蔬菜中的对硫磷.     

米托蒽醌在金电极上的电化学研究及其应用

米托蒽醌(MTX)在0.2 mol/L B-R缓冲溶液(pH=1.5)中循环伏安扫描时,在金电极上会产生一个灵敏的氧化峰P1(峰电位为1.087 V)和两个灵敏的还原峰P2(峰电位为0.817 V)、P3(峰电位为0.764 V)。P1峰电流值与MTX浓度在1.0×10-9~1.0×10-6mol/L范围内呈良好的线性关系;其检出限可达5.6×10-10mol/L。本研究优化了测定米托蒽醌的最佳实验条件,建立了可灵敏测定米托蒽醌的新方法;同时对米托蒽醌在金电极上的电化学行为进行了较为详细的研究。     

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.     

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.     

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^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

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。