示波极谱法同时测定两种氨基酸

在蛋白质中的谷氨酸和天门冬氨酸的电分析方法,目前只有单个测定方法,未见有连续测定方法的报道.本文研究了在浓度为0.020g/L谷氨酸和0.010 g/L天门冬氨酸,pH为3.5～4.5的硼酸体系中同时出现两灵敏度和分辨率均比较高的极谱波,峰电位分别为0.30V和0.60V,检出限分别为0.0050g/L和0.0025g/L,当其浓度分别为0.0100～0.1000g/L和0.005～0.05g/L与峰电流呈线性关系.浓度为0.500g/L胱氨酸、酪氨酸、亮氨酸、脯氨酸等中性氨基酸对测定无大的影响.回收率分别为95.0～100.1%和96.5～101.6%,未发现有系统误差存在.经3次对人发水解液分析,并与氨基酸分析仪测量结果对照,平均值分别为9.50%和9.55%,相对误差为1.50%和1.80%,均在国家规定的范围内.本法简便快速,灵敏度高,稳定性好,可用于各种蛋白质中的谷氨酸和天门冬氨酸的测定.     

高效液相色谱法测定羊水中兴奋性氨基酸、抑制性氨基酸的含量

建立了反相高效液相色谱法测定羊水中兴奋性氨基酸天门冬氨酸、谷氨酸,抑制性氨基酸甘氨酸含量的方法,色谱柱为LUNAC18柱(4.6mm×250mm,5μm),流动相为乙腈水(V/V),按低压梯度洗脱,梯度系统0～4min,乙腈40%;4～20min,乙腈40%～52%;20～30min,乙腈52%～60%;30～40min,乙腈60%～40%。流速0.8mL/min,柱温40℃,紫外检测波长260nm;进样量10μL。结果显示,天门冬氨酸、谷氨酸和甘氨酸三者的线性范围均为2.5～85mg/L;标准加入的回收率为99.6%～102.6%。本方法灵敏度高、测定结果可靠。用本方法对201例不同孕期的羊水作兴奋性和抑制性氨基酸检测,发现羊水中3种氨基酸随妊娠进展而增加的趋势,胎儿畸形或宫内缺氧时羊水中这3种氨基酸水平明显升高。     

聚L-白氨酸修饰电极伏安法测定痕量多巴胺的研究

用循环伏安法制备了聚L-白氨酸修饰玻碳电极,研究了多巴胺在聚L-白氨酸修饰玻碳电极上的电化学行为,建立了循环伏安法测定痕量多巴胺的新方法。实验结果表明,在pH 6.0的磷酸盐缓冲溶液中,多巴胺在聚L-白氨酸修饰玻碳电极上产生一对灵敏的氧化还原峰,峰电位分别为Epa=0.281V,Epc=0.170 V(相对Ag/AgCl电极)。峰电流与多巴胺的浓度在5.0×10-8~5.0×10-4mol/L的范围内有线性关系,检出限为5.0×10-9mol/L。对1.0×10-5mol/L多巴胺溶液平行测定9次,其相对标准偏差为4.0%。已用于针剂中多巴胺的测定。     

整体式PDMS电泳芯片快速成型及高灵敏化学发光检测氨基酸

通过再铸模法将聚二甲基硅氧烷(PDMS)预聚物固化在由微细金属丝构成的微流体孔道的印模中,一次成型制作了整体式PDMS芯片.将所制作的芯片与化学发光检测器集成构建了微芯片毛细管电泳分析系统.初步考察了不经过衍生化时该系统分离检测氨基酸的性能.实验结果表明,精氨酸和天门冬氨酸在80s内完全分离,分离度为2.45,精氨酸的浓度检测限为3.50μmol/L.     

聚天冬氨酸和钨酸钠复配对3%NaCl溶液中白铜B10的缓蚀作用

应用交流阻抗法和极化曲线法,研究了两种环境友好型水处理药剂,即聚冬天氨酸(PASP)和钨酸钠的单一配方及其复配对白铜(B10)在3%NaC l溶液中的缓蚀效果.研究表明:单一聚冬天氨酸或钨酸钠配方对B10均具有一定的缓蚀效果,其中聚冬天氨酸以浓度为40 mg/L,钨酸钠以浓度为60 mg/L时的缓蚀效果最佳.总浓度为40 mg/L的两者复配具有更加明显的缓蚀效果并显示出协同效应,其中以聚冬天氨酸与钨酸钠配比为3∶1的缓蚀效果最佳.     

新型手性脂质性酰胺型大环多胺配体的合成

酰胺型大环多胺同时具有大环多胺和寡聚肽(Ｏｌｉｇｏｐｅｐｔｉｄｅｓ)的结构特点 ,从而产生独特的物理化学性质 ,并且某些过渡金属配合物具有特殊的催化活性和生物功能 ,因而受到广泛关注和重视[1～ 6] 。它们在催化氧化、金属酶模型、分子识别和材料化学等方面已得到广泛的研究。然而 ,将手性引入酰胺型大环多胺形成手性酰胺型大环多胺的报道并不多见[7～1 1 ] 。近年来 ,我们报道了长链酰胺型大环多胺的合成以及构成的金属胶束超分子体系模拟水解金属酶[1 2 ,1 3] 。本文则以廉价的Ｌ 天门冬氨酸和Ｌ 谷氨酸为起始原料简便地合成了一类…     

新型手性羟基噁唑啉配体的合成及其在N-二苯基次磷酰亚胺的不对称乙基锌加成反应中的应用

以L-天门冬氨酸为原料,经两步反应合成了两种新的手性嗯唑啉配体(1f和2f),其结构经1H NMR,13C NMR,IR,HR-MS-ESI表征.将1f或2f用于催化N-二苯基次磷酰亚胺的不对称乙基锌加成反应,获得了较高的对映选择性,e.e.值高达96%,产率85%.     

测定脑脊液中兴奋性氨基酸的样品前处理方法

采用高效相色谱法，研究脑脊液样品不同的前处理方法对脑脊液中兴奋性氨基酸（谷氨酸、天门冬氨酶）测定结果的影响。结果表明，强酸性蛋白沉淀剂可导致脑脊液中的谷氨酸异常增高，脑脊液贮存于－80℃并以甲醇作为蛋白沉淀剂时，兴奋氨基酸稳定，测定结果不变；如果脑脊液贮存在－20℃，不能超过8周，建立了准确、灵敏的兴奋性氨基酸分析方法，为临床拮抗兴奋性毒性和进一步深入研究兴奋性氨基酸提供可靠的测定方法。     

槲皮素在聚L-络氨酸修饰电极上的电化学行为及测定

采用电聚合方法制备了聚L-络氨酸修饰电极。利用循环伏安法(CV)探究了pH值、扫描速率对槲皮素电化学行为的影响。用差分脉冲伏安法(DPV)对槲皮素进行测定。结果表明:聚L-络氨酸修饰电极在pH值为6.0的磷酸盐缓冲溶液中对槲皮素表现出良好的电催化能力。在6.21×10~(-5)～6.9×10~(-4) mol/L范围内槲皮素的浓度与相应的检测信号呈现出良好的线性关系,线性方程为:I(10~(-6) A)=-1.034 8-0.099 39c(10~(-4) mol/L),线性相关系数R=-0.987 87,检出限为2.07×10~(-5) mol/L(S/N=3)。电化学分析方法简易快捷、重现性和稳定性高。     

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.     

探究“铁的锈蚀条件”实验创新设计

设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。