毛细管胶束电动色谱法分离PTC氨基酸

１引言用毛细管胶束电动色谱（ＭＥＫＣ）对ＰＴＣ氨基酸分离条件进行研究，建立ＭＥＫＣ分离１７种ＰＴＣ氨基酸的方法。结果表明，在２０ｍｉｎ内１７种ＰＴＣ氨基酸得到比较满意的分离，方法回收率为９５％～１０３％，在６０μｍｏｌ／Ｌ浓度范围内均呈线性，相关系数ｒ＞０．９９２；最低检测限为０．１５－０．４０ｐｍｏｌ。用该法对灵芝菌丝中氨基酸含量进行测定并与ＨＰＬＣ法进行比较，二者无显著性差异（α＝０．０５）。２实验部分２．１仪器和试剂ＨＰ－１型高效毛细管电泳仪（中国专利：９４１１１５６４ｘ，河北大学研制），…     

化学气相传输法分离稀土混合氧化物Sm2O3-Eu2O3-Gd2O3

以ＡｌＣｌ３ 为络合物配体, 研究Ｓｍ２Ｏ３Ｅｕ２Ｏ３Ｇｄ２Ｏ３ 的分离特性。结果表明, 其传输能力为：Ｓｍ ≈Ｇｄ＞ Ｅｕ, 氯化物主要在９８０ ～１１００ Ｋ 沉积。不同温区的最大分离系数分别为： βＥｕ／Ｓｍ;１２００ Ｋ＝ １－７０ ,βＥｕ／Ｇｄ;１３００ Ｋ＝ １－８８ , βＳｍ／Ｇｄ;１３００ Ｋ ＝ １－２４ , β′Ｓｍ／Ｅｕ;８５０ ～８８０ Ｋ＝ ２－７６ , β′Ｇｄ／Ｅｕ;８８０～９００ Ｋ ＝ ２－８３ , β′Ｇｄ／Ｓｍ;８００ Ｋ＝１－１２ , 高于传统的湿法分离系数。     

脱氧核糖核酸变性和损伤的吸附伏安法研究

本文用汞电极（ＨＭＤＥ）二次导数阴极吸附伏安（ＳＤ－ＡｄＣＳＶ）和碳电极（ＧＣＥ、ＣＰＥ）导数循环伏安（ＦＤ－ＣＶ）法研究了核酸受热、紫外线、超声波和丝裂霉素Ｃ（ＭＭＣ）作用下的变性作用。在０．１ｍｏｌ／Ｌ（Ｋ２ＨＰＯ４＋ＫＨ２ＰＯ４）－０．１ｍｏｌ．Ｌ ＮａＣｌ（ｐＨ７．０）底液中，吸附的单股（ｓｓ－）和双螺旋（ｄｓ－）ＤＮＡ分别在ＨＭＤＥ上得到特征还原峰Ｐ３和Ｐ２，和在碳电极上得到氧化峰Ａ。物     

化学气相色传输法分离稀土混合氧化物Sm2O3—Eu2O3—Gd2O3

以ＡｌＣｌ３为络合物配体,研究Ｓｍ２Ｏ３－Ｅｕ２Ｏ３－Ｇｄ２Ｏ３的分离特性。结果表明,其传输能力为：Ｓｍ≈Ｇｄ〉Ｅｕ,氯化物主要在９８０￣１１００Ｋ沉积。没温区的最大分离系数分别为：βＥｕ／Ｓｍ：１２００Ｋ＝１．７０,βＥｕ／Ｇｄ;１３００Ｋ＝１．８８,βＳｍ／Ｇｄ;１３００Ｋ＝１．２４,βＳｍ／Ｅｕ;８５０￣８８０Ｋ＝２．７６,βＧｄ／Ｅｕ;８８０￣９００Ｋ＝２．８３,βＧｄ／Ｓｍ;８００Ｋ＝１     

ASYMMETRIC SYNTHESIS ⅩⅩⅧ: ENANTIOSELECTIVE REDUCTION OF AROMATIC KETONES CATALYZED BY NEW CHIRAL CATALYST-(4R,8R,9S)-CAMPHANE[8,9-b]-1,3,2-OXATHIOBOROLIDINE

ＡＳＹＭＭＥＴＲＩＣＳＹＮＴＨＥＳＩＳⅩⅩⅧ：ＥＮＡＮＴＩＯＳＥＬＥＣＴＩＶＥＲＥＤＵＣＴＩＯＮＯＦＡＲＯＭＡＴＩＣＫＥＴＯＮＥＳＣＡＴＡＬＹＺＥＤＢＹＮＥＷＣＨＩＲＡＬＣＡＴＡＬＹＳＴ－（４Ｒ，８Ｒ，９Ｓ）－ＣＡＭＰＨＡＮＥ［８，９－ｂ］－１，３，...     

水杨醛－L－甲硫氨酸希夫碱钴（Ⅱ）配合物的热分解动力学

本文合成了一种新的希夫碱配合物，水杨醛－Ｌ－甲硫氨酸—水合钴（Ⅱ），Ｃｏ（ｓａｌｍｅｔ）·Ｈ２Ｏ，并用非等温热重法研究了它的热分解反应动力学。ＴＧ及ＤＴＧ曲线表明配合物按两步分解：Ｃｏ（ｓａｌｍｅｔ）·Ｈ２Ｏ１４２－１７５℃（１）→Ｃｏ（ｓａｌｍｅｔ）１７５－８２０℃（２）→ＣｏＯ用Ａｒｃｈａｒ微分法和Ｃｏａｔｓ－Ｒｅｄｆｅｒｎ积分法联合求出两步骤的动力学。步骤（１）、（２）的动力学方程分别表示如下：ｄα／ｄｔ＝Ａ·ｅ－Ｅ／ＲＴ（１－α）［－ｌｎ（１－α）］ｄα／ｄｔ＝Ａ·ｅ－Ｅ／ＲＴ（１－α）２［（１－α）－１－１］     

微电极阵列若干电化学特性的研究

用微电子平面工艺制备了带宽和边长分别为１０、２０、３０μｍ的带形和正方形微电极阵列（ＢＭＥＡ和ＳＭＥＡ）。在Ｋ３Ｆｅ（ＣＮ）６溶液中研究了它们的电化学特性。边长为１０μｍ的ＳＭＥＡ（工作电极总面积仅为９×１０＾－３ｍｍ＾２）有最大的电流密度（１２．１μＡ／ｍｍ＾２）和最短的响应时间（５ｓ）。同一硅片中任选５个ＳＭＥＡ其Ｈ２Ｏ２工作曲线的线性范围为０．１～５ｍｍｏｌ／Ｌ，平均斜率为２２０ｎＡ／ｍｍｏ     

多核Nd-Al双金属配合物对丁二烯的聚合 Ⅳ.烷基铝种类的影响

利用多核Ｎｄ－Ａｌ双金属配合物可单独引发双烯烃聚合的特点，考察了烷基铝种类对丁二烯加聚过程的影响，并与一般混合稀土催化体系进行了比较．烷基铝对活性体催化活性的影响与其用量有关，低ｎ（Ａｌ）／ｎ（Ｎｄ）值时，活性次序为：ＡｌＭｅ３，ＡｌＥｔ３，ＨＡｌＢｕｉ２＞Ａｌ（Ｃ８Ｈ１７）３＞ＡｌＢｕｉ３；高ｎ（Ａｌ）／ｎ（Ｎｄ）值时，活性次序相反：ＡｌＭｅ３，ＡｌＥｔ３，ＨＡｌＢｕｉ２＜Ａｌ（Ｃ８Ｈ１７）３＜ＡｌＢｕｉ３．烷基铝链转移作用强弱次序为：ＨＡｌＢｕｉ２≥ＡｌＥｔ３＞ＡｌＢｕｉ３＞ＡｌＭｅ３＞Ａｌ（Ｃ８Ｈ１７）３．根据聚丁二烯微观结构与其分子量的关系，可将烷基铝对聚丁二烯顺式含量的影响分为３类：（１）ＡｌＥｔ３和Ａｌ（Ｃ８Ｈ１７）３；（２）ＨＡｌ－Ｂｕｉ２和ＡｌＢｕｉ３；（３）ＡｌＭｅ３．所得结果有助于对稀土催化定向聚合过程的深入了解．     

气相色谱法测定化妆品中的 VE 含量

介绍了一种用气相色谱法准确快速测定品中ＶＥ２含量的新方法。该法以ＶＣ作保护剂,用环已烷提取样品,ＳＥＰ－ＰＡＫ ＡＬＵＭ－Ａ小柱净化。以氯氰菊酯内标物,在１？５％ＯＶ＝－１７色谱柱上进行分离,测定化妆口中ＶＥ含量。内标物与样品的分离度为１．５５。平均回收纺为９４．３％～９８．８％,相对标准偏差为１．７％～３．５％（ｎ＝５）。     

VAPOR-PHASE ALKYLATION OF BENZENE WITH PROPYLENE OVER SiW_(12)/C CATALYST

ＶＡＰＯＲ－ＰＨＡＳＥＡＬＫＹＬＡＴＩＯＮＯＦＢＥＮＺＥＮＥＷＩＴＨＰＲＯＰＹＬＥＮＥＯＶＥＲＳｉＷ_（１２）／ＣＣＡＴＡＬＹＳＴＣｈｕ，Ｗｅｎｌｉｎｇ；Ｙａｎｇ，Ｘｉａｎｇ－ｇｕａｎｇ；Ｙｅ，Ｘｉｎｇ－ｋａｉａｎｄＷｕ，Ｙｕｅ（ＣｈａｎｇｃｈｕｎＩ?..     

高效液相色谱法分离测定洛伐他汀及其开环酸

改进了洛伐他汀的分析方法，以甲醇：水＝80：20为流动相，采用紫外检测器检测，使用C4色谱柱定性、定量分析了洛伐他汀及洛伐他汀羟基酸，并得出了相关方程．实验证明，采用新的色谱条件可在有效地分析洛伐他汀及其开环酸的基础上，节约分析成本．     

Optimization of the conditions for biuret complex formation for the determination of peptides by capillary electrophoresis with ultraviolet detection

Capillary electrophoresis with UV detection was utilized to optimize copper complexation conditions for the analysis of neuropeptides. Complexation was confirmed by monitoring the response at a visible wavelength. Four complexation strategies were used to compare the UV response of native peptides and their respective copper complexes. All four strategies resulted in complete complexation, but on-capillary complexation provided significant advantages over precapillary and pre-/on-capillary. An increase in UV absorbance along with peak stacking resulted in a significantly greater response using the on-capillary technique. Also, on-capillary complexation does not require dilution of the sample. The effects of temperature and copper concentration were also investigated. The utility of this method for the separation of an enkephalin peptide mixture is presented.     

反相高效液相色谱法测定苯醚甲环唑原药的含量

建立了反相高效液相色谱法测定苯醚甲环唑原药含量的方法,乙腈―水（体积比60∶40）为流动相,检测波长225 nm,流速1.0 m L/min,ODS C18色谱柱（250 mm×4.6 mm（i.d.）,2.5um）,紫外检测器。平均回收率为103.6%,标准偏差为0.37%,变异系数为0.38%;方法线性相关性系数0.999 7,适用于产品质量的检测分析。     

Determination of enkephalin peptides by nonaqueous capillary electrophoresis with electrochemical detection

Nonaqueous capillary electrophoresis with electrochemical detection (NACE-ED) was applied to the analysis of enkephalin peptides. The effect of different buffer compositions on the electrophoretic behavior of methionine enkephalin, leucine enkephalin, and [D-Ala2]-leucine enkephalin was studied. Separation of the protonated and the deprotonated peptides was obtained using ACN/methanol-based electrolyte systems. The electrochemical behavior of the enkephalins was studied by the capillary batch injection analysis technique. NACE-ED yielded well-defined signals in the oxidation mode only for the negatively charged analytes. The optimized BGE for the counterelectroosmotic separation consisted of 10 mM ammonium acetate in ACN/methanol (3:1 v/v). Using a platinum microdisk electrode set to an actual potential of +0.65 V detection limits in the submicromolar range were observed which are about one order of magnitude lower compared to UV detection. Problems concerning EOF instability and electrode fouling caused by water and other neutral sample impurities transported by the EOF can be avoided in the EOF-inverted mode using poly(ethylene glycol)-coated capillaries and an actual working electrode potential of +1.0 V. For the quantification of the enkephalins [D-Ala2]leucine enkephalin was used as internal standard. The practical utility for the determination of enkephalins in spiked plasma samples after SPE was demonstrated.     

Effect of Mobile Phase Components on the Separation of Polypeptides Using Carbon Dioxide-Based Mobile Phases

The effect of mobile phase modifier and additive on the chromatographic properties of various small polypeptides was explored under subcritical conditions. A polymeric column was used to separate various enkephalin analogs, bradykinin, and oxytocin using a carbon dioxide-based mobile phase with either an ethanol or a 2-methoxyethanol modifier. The role of the modifier was found to be secondary to that of the mobile phase additive. As progressively stronger acidic mobile phase additives were used, the peak profiles of the various polypeptides improved and retention decreased. Heptadecafluorooctanesulfonic acid was found to be the most useful additive for these types of solutes under near-critical conditions, while the potassium salt of heptadecafluorooctanesulfonic acid failed to elute any of the polypeptides. At low temperatures, pressure gradients with a carbon dioxide/ethanol/heptadecafluorooctanesulfonic acid ternary mobile phase produced reasonably good peak profiles with the polymeric column.     

Gas-phase dissociation pathways of multiply charged peptide clusters

Numerous studies of cluster formation and dissociation have been conducted to determine properties of matter in the transition from the condensed phase to the gas phase using materials as diverse as atomic nuclei, noble gasses, metal clusters, and amino acids. Here, electrospray ionization is used to extend the study of cluster dissociation to peptides including leucine enkephalin with 7–19 monomer units and 2–5 protons, and somatostatin with 5 monomer units and 4 protons under conditions where its intramolecular disulfide bond is either oxidized or reduced. Evaporation of neutral monomers and charge separation by cluster fission are the competing dissociation pathways of both peptides. The dominant fission product for all leucine enkephalin clusters studied is a proton-bound dimer, presumably due to the high gas-phase stability of this species. The branching ratio of the fission and evaporation processes for leucine enkephalin clusters appears to be determined by the value of z²/n for the cluster where z is the charge and n the number of monomer units in the cluster. Clusters with low and high values of z²/n dissociate primarily by evaporation and cluster fission respectively, with a sharp transition between dissociation primarily by evaporation and primarily by fission measured at a z²/n value of 0.5. The dependence of the dissociation pathway of a cluster on z²/n is similar to the dissociation of atomic nuclei and multiply charged metal clusters indicating that leucine enkephalin peptide clusters exist in a state that is more disordered, and possibly fluid, rather than highly structured in the dissociative transition state. The branching ratio, but not the dissociation pathway of [somatostatin₅ + 4H]⁴⁺ is altered by the reduction of its internal disulfide bond indicating that monomer conformational flexibility plays a role in peptide cluster dissociation.     

Development and Validation of High‐Performance Liquid Chromatographic Method for Estimation of Lercanidipine in Rabbit Serum

Abstract

A new, simple, and sensitive reverse‐phase liquid chromatographic method was developed and validated for the estimation of Lercanidipine hydrochloride in rabbit serum using UV detector under isocratic conditions. After subjecting serum to simple and efficient one‐step extraction procedure, 100 µl of sample was injected onto high‐performance liquid chromatography system. The detector response was linear in the concentration range of 25–1000 ng/ml. The developed method was validated as per standard guidelines. Validation demonstrated accuracy, precision, and selectivity of the proposed method. The drug was found to be stable under various processing and storage conditions.     

Photochemical phase transition versus photochemical phase separation

When a nematic liquid crystal is doped with a large amount of a liquid crystalline azobenzene compound (15 wt %), the photoisomerization of azobenzene under UV and visible light irradiation can give rise to reversible and interconvertible photochemical phase transition and photochemical phase separation. Both normal and reverse modes of photocontrolled switching of transmittance through crossed polarizers can be realized with the same mixture of liquid crystal/azobenzene dopant.     

LC and LC-MS Separation of Peptides on Macrocyclic Glycopeptide Stationary Phases: Diastereomeric Series and Large Peptides

Previous work on the LC separation of peptides had shown that macrocyclic glycopeptide stationary phases to be selective for peptides of five to thirteen amino acids in length. In this work, the selectivity of the teicoplanin stationary phase is compared to that of a C18 stationary phase for seven diastereomeric enkephalin peptides. The teicoplanin stationary phase separated all seven diastereomeric enkephalin peptides in a single chromatographic run. The insertion of d-amino acids into the primary enkephalin sequence produced areas of hydrophobicity that influenced retention order on the C18 stationary phase. However, analogous trends are not observed on the teicoplanin stationary phase, which is more polar and structurally diverse. Optimization of the mobile phase and the use of a step-gradient for the enkephalin separation on the teicoplanin stationary phase is discussed. Also, the selectivity of macrocyclic glycopeptide stationary phases for peptides of 14, 28, 30, and 36 amino acids also is investigated and compared to separation on a C18 stationary phase. A method for eluting peptides with multiple basic amino acids, which tend to be strongly retained on the macrocyclic glycopeptide stationary phases, is presented.     

离子液体作高效液相色谱流动相添加剂测定水杨酸

建立了以离子液体作反相高效液相色谱流动相添加剂测定水杨酸的方法.实验以ZORBAX ODS反相色谱柱为分离柱,采用紫外检测方法,研究了检测波长、离子液体烷基链长度、离子液体溶液的浓度以及pH值等对分离和测定的影响.优化的色谱条件为:以体积比60:40的甲醇-3.0 mmol/L1-丁基-3-甲基咪唑四氟硼酸盐溶液(乙酸...