高效液相色谱法测定杜仲中京尼平甙酸

ODS- C18色谱柱 (2 0 0 mm× 4 .6 mm,5 μm) ,甲醇 -水 -冰乙酸 (12∶ 87∶ 1)为流动相 ,高效液相色谱法测定了杜仲中京尼平甙酸的含量 ,考察了流动相组成、酸性添加剂对色谱分离效果的影响 ,流速 1.0 m L/ min时 ,京尼平甙酸的容量因子 k′在 2— 3之间 ,分离度大于 1,保留时间为 6 .9min,样品分析时间在 30 min之内 ,满足色谱分析要求。京尼平甙酸在 0 .0 36— 1.36 mg/ m L时 ,色谱峰面积与样品量呈良好的线性关系 ,线性方程为 A=6 375 6 132 72 6 0 C,相关系数 r=0 .9996。     

氨基甲酸酯类农药残留的加压毛细管电色谱法测定

采用加压毛细管电色谱 -紫外检测法 ,建立了速灭威、克百威和残杀威三种氨基甲酸酯类农药的同时分离检测方法。采用反相 C18毛细管电色谱柱 (3μm,2 0 0 mm× 75 μm I.D.) ,以乙腈∶ PBS(5 mmol/ L,p H6 .5 0 ) =30∶ 70 (V/ V)为流动相 ,检测波长 2 2 0 nm,流速 10 0 μL/ min,柱压 6 .9MPa,在电色谱柱末端施加10 .0 k V负电 ,三种物质在 10 min内基线分离。该法用于蔬菜中速灭威、克百威和残杀威的残留分析研究 ,效果令人满意     

高效液相色谱法测定小儿盐酸二氧异丙嗪冲剂的含量

采用高效液相色谱法测定盐酸二氧异丙嗪的含量。色谱柱为 DIKMATMRPC18(4 .6 mm× 2 0 cm,5 μm) ,流动相为乙腈 - 0 .5 %磷酸二氢钾 -三乙胺 (5 0∶ 5 0∶ 0 .2 ) ,用磷酸调 p H值至 6 .8± 0 .1;流速为1.0 m L/ min,检测波长为 2 6 4nm。该法回收率为 99.6 % ,RSD=0 .6 1%。盐酸二氧异丙嗪在浓度为0 .0 184 8— 0 .0 4 312 mg/ m L范围内线性关系良好。相关系数为 r=0 .9999。该方法操作简便 ,结果准确可靠。     

高效液相色谱法测定2-苯基-4-对甲苯基-1,5-苯并硫氮杂-α-(丁二酰亚胺基)-β-内酰胺

本文采用 Hypersil- ODS2 (4 .6mm× 2 5 0 mm,5μm)色谱柱 ,乙腈 -水 (70∶ 30 )流动相 ,2 4 2 nm测定波长 ,建立了测定 2 -苯基 4 -对甲苯基 - 1,5 -苯并硫氮杂 艹卓 -α- (丁二酰亚胺基 ) -β-内酰胺高效液相色谱法。该法线性范围为 0— 0 .1mg/ m L,回归方程 A=2 .11× 10 8C- 3.10× 10 5,相关系数 r=0 .9995 ,相对标准偏差为0 .2 4 % (C=0 .0 6mg/ m L,n=5 ) ,检出限为 0 .0 5 μg/ m L。平均回收率在 97.1%— 10 2 .4 %之间。该法重现性好、灵敏度高、简单、快速、准确     

高效液相色谱法测定杀虫剂灭幼脲三号的含量

本文采用 Hypersil- ODS2 ( 4 .6mm× 2 50 mm,5μm)柱 ,乙腈 -水 - N,N-二甲基甲酰胺 ( 60∶ 4 0∶ 0 .1)为流动相 ,测定波长为 2 54nm,建立了测定灭幼脲三号的高效液相色谱法。该法线性范围为 2 .0— 80μg/m L,回归方程为 A=52 .4 1C+0 .1936,相关系数 r=0 .9987,精密度为 3.5% ( n=11,C=4 0μg/m L) ,检出限为 0 .0 5μg/m L。平均回收率在 96%— 10 4 %之间 ,已用于 2 5%水剂样品的测定 ,结果令人满意。     

高效液相色谱法测定富马酸异哌丙吡仑

采用高效液相色谱法测定富马酸异哌丙吡仑的含量。色谱柱为 DIKMATMRPC18(4 .6 mm× 2 0 cm,5 μm) ,流动相为乙腈 - 0 .5 %十二烷基硫酸钠 -三乙胺 (5 5∶ 4 5∶ 0 .2 ) ,用冰醋酸调 p H值至 7.0± 0 .1;流速为 1.0 m L/ min,检测波长为 2 6 5 nm。该方法回收率为 99.8% ,RSD=0 .4 4%。富马酸异哌丙吡仑在浓度为0 .0 5 92 8— 0 .1383mg/ m L范围内线性关系良好。相关系数为 r=0 .9997。该方法操作简便 ,结果准确可靠。     

高效液相色谱法测定2-对甲氧基苯基-4-苯基-1,5-苯并硫氮杂-α-(丁二酰亚胺基)-β-内酰胺

应用高效液相色谱外标定量法对 2 -对甲氧基苯基 - 4 -苯基 - 1,5 -苯并硫氮杂 艹卓 -α- (丁二酰亚胺基 ) -β-内酰胺进行了测定。采用 Hypersil- ODS2 ( 4 .6mm× 2 5 0 mm,5 μm)柱 ,乙腈与水按 70∶ 30 ( V/ V)组成流动相 ,测定波长为 2 4 2 nm,该方法线性范围为 0— 0 .1mg/ m L ,回归方程 A=1.91× 10 8C- 3.82× 10 5,相关系数 r=0 .9994 ,相对标准偏差为 0 .72 %,检出限为 0 .0 5μg/ m L,平均回收率在 98.4 %— 10 1.8%之间。该法重现性好、灵敏度高、简单、快速。     

反相高效液相色谱法测定1-(4-硝基苯)-3-(5-溴-2-吡啶)-三氮烯

ZORBAX Eclipse XDB- C8(4.6× 1 5 0 mm,5 μm)色谱柱 ,乙腈流动相 ,流速 0 .6 0 m L/min,检测波长4 2 0 nm,反相高效液相色谱法测定 1 - (4-硝基苯 ) - 3- (5 -溴 - 2 -吡啶 ) -三氮烯。该法的线性范围为 1—1 0 .0 μg/m L,线性回归方程为 A=5 .91 5 4 .4 37C,相关系数 0 .9989,相对标准偏差为 0 .8973%(C=7.2 0 μg/m L,n=5 ) ,检出限为 0 .0 2 872 μg/m L,平均回收率在 93.2 %— 1 0 2 .2 %之间。     

高效液相色谱法测定金盏菊中叶黄素

KNAUER Eurospher- 1 0 0 C1 8(3.9mm× 30 0 mm,4 .6 μm)色谱柱 ,以乙腈 -甲醇 -乙酸乙酯混合液为流动相 ,流速 1 .0 m L/ min;检测波长 4 6 0 nm;柱温 2 5℃ ,高效液相色谱法测定金盏菊中叶黄素含量。校准曲线法定量 ,检出限为 3.0 mg/ m L。叶黄素含量在 8— 6 4mg/ L之间线性关系良好 ,r=0 .9999,RSD=1 .4 % ,回收率在 97%— 1 0 1 %之间。本法适合叶黄素产品中叶黄素含量的测定     

2-(1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸光度法测定铜的研究

本文研究了新显色剂 2 - ( 1,3,4 -三氮唑偶氮 ) - 5 -二乙氨基苯甲酸 ( TZDBA)与铜显色反应的条件。在0 .1mol/L的 HCl介质中 ,TZDBA与 Cu2 +形成稳定的紫红色络合物。其最大吸收波长在 5 78nm处 ,表观摩尔吸光系数为 4 .0× 10 4 L· mol-1·cm-1,Cu2 +质量浓度在 0— 10 μg/2 5 m L范围内符合比耳定律。所拟方法可不经分离直接测定镁合金和铝合金标样中的微量铜 ,加标回收率为 10 1.0 %— 10 1.4 % ,RSD( n=6)为 2 .0 %— 3.9% ,结果令人满意     

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Linear and Nonlinear Raman Spectroscopy onⅡ-Ⅵ Semiconductor Quantum Wires and Dots

1.ＩｎｔｒｏｄｕｃｔｉｏｎＮａｎｏｓｔｒｕｃｔｕｒｅｄｓｅｍｉｃｏｎｄｕｃｔｏｒｓｗｉｔｈｓｐａｔｉａｌｄｉｍｅｎｓｉｏｎｓｏｆｆｅｗｎａｎｏｍｅｔｅｒｓａｎｄｌｅｓｓｓｈｏｗｃｅｒｔａｉｎｏｐｔｉｃａｌｐｒｏｐｅｒｔｉｅｓ,ｔｈａｔａｒｅｑｕｉｔｅ?..     

Of heat capacity at homologous temperatures for metals showing h.c.p. ⇄ b.c.c. transformation

Some interesting aspects of the temperature dependence of the Planck’s functionφ and heat capacities of metals exhibiting the h.c.p. ⇄ b.c.c. transformation have been brought to light by the use of reduced temperature (T*) and Planck’s function (-φ T*). It has been shown that tangents drawn to the -φ T* vsT* plots of these metals at any chosen value ofT* intersect at a point whose coordinates are defined by the slope and intercept ofφ vs entropy plots at any homologous temperature and the selectedT* value. A generalized expression obtained for the temperature dependence ofφ has been used to demonstrate that the heat capacity of these metals may be visualized to have structural and material components.     

威耳逊对云室的实验研究

介绍了C.T.R.威耳逊的主要贡献和发明云室的过程.他由研究水滴的凝结规律入手,不断改进实验装置,拍摄了带电粒子的径迹照片,从而证明了康普顿效应;还分析了威耳逊取得成功的几个重要因素.     

E.S.R. Spectra of the Cyclobutanesemidiones Derived from Three Tricyclo[4. 4. 2. 01,6,]Dodecane-11-OL-12-Ones

The semidione radical anions derived from a variety of alicyclic ketones and α-hydroxyketones have been extensively investigated via esr by Russell and co-workers.¹Studies of the chemistry and spectra of the 1, 2-cyclobutanediones derived from the tricyclo[4. 4. 2. 0^1,6] dodecane-11-o1-12-one system²suggested that an examination of the esr spectra of the related semidiones would be of considerable interest. The recent reports on the esr spectra of cyclobutanes emidione^1cand several substituted cyclo-butanes emidiones^1bfurther prompt this communication.     

Photolysis and E. S. R. Studies on Triphenylphosphinecarbethoxymethylene

Although several different groups have studied the photolysis of phosphorus ylides, none have utilized e. s. r. to support the postulated decomposition mechanisms. The fundamental question which awaits a definitive answer is which bond breaks first upon photolysis. Tschesche¹ and de Silva² utilizing the ylides (1) and (2) suggested that the carbon-phosphorus double bond was initially broken while Nagao³ using (3) proposed phenyl-phosphorus bond cleavage.     

Bulk viscous L.R.S. Bianchi type V tilted stiff fluid cosmological model in general relativity

Locally rotationally symmetric (L.R.S.) Bianchi type V bulk viscous tilted stiff fluid cosmological model is investigated. To get the deterministic model of the universe, we have also assumed a condition A=Bⁿ between metric potentials A, B where n is the constant. The behaviour of the model in presence and absence of bulk viscosity and singularities in the model are also discussed. In general, the models represent accelerating, shearing, tilted and non-rotating universe. The models have point type singularity in presence and absence of bulk viscosity both.     

A. C. conductivity due to intimate pairs of charged defect centres

The influence of the association of charged defects into intimate pairs on a.c. conduction is discussed in the light of the fundamental mechanism being that of the simultaneous hopping of two electrons over the barrier separating two oppositely charged defect centres, the barrier height being correlated with the intersite separation via the Coulomb interaction. The behaviour of chalcogenide glasses is discussed in terms of the present theory, and it is concluded that the existence of two classes of a.c. conductivity behaviour into which these materials generally fall can be simply explained by the predominance of either intimate pairs or non-intimate pairs of charged defect states according to the conditions of preparation.     

凹叶厚朴各部位挥发油成分比较研究

采用顶空固相微萃取(HS-SPME)提取凹叶厚朴不同部位的挥发油成分,气相色谱-质谱(GC-MS)分析其组成.结果显示:根鉴定出19个化合物,其中4(14),11-桉叶二烯(26.04％),(1S-顺)-1,4-二甲基-7-(1-甲基亚乙基)-奠(24.94％),石竹烯(9.41％),β-桉叶醇(7.28％)为主要成分...     

W.R. Grove and the fuel cell

Though known these days largely because he invented the fuel cell, Grove also had many other distinguished achievements to his credit. His monumental book On the Correlation of Physical Forces contained all the arguments that led to the enunciation of the first law of thermodynamics. He was also an extremely versatile natural philosopher who was, in addition, well versed in classical literature, particularly the works of the eminent scholars of ancient Greece and Rome. This article touches upon these qualities, but is predominantly concerned with the emergence and modern aspects of the H₂/O₂ fuel cell and its potential for the clean generation of energy.