Capillary Electrochromatography of Pyrimidine Derivatives Using UV and Mass Spectrometric Detection

 The separation of pyrimidine derivatives by capillary electrochromatography (CEC) using either UV or mass spectrometric detection is described. For UV detection an aqueous phosphate carrier electrolyte containing acetonitrile is employed. The results are compared to the analysis of the same compounds by micellar electrokinetic chromatography in terms of selectivity, migration times, linearity, and detection limits. For the combination of CEC and mass spectrometry (MS) an inexpensive way to couple commercially available instruments is presented; the interface consists of an electrically grounded stainless steel connector (containing a stainless steel frit) serving as the electrode and coupling the CEC capillary with a fused silica transfer capillary to the MS instrument. Alternatively, a PEEK adapter combining the CEC capillary and a grounded stainless steel transfer capillary serving as the electrode is employed. To avoid the formation of hydrogen gas at the coupling piece or the transfer capillary, p-benzoquinone is added to the carrier electrolyte consisting of aqueous ammonium acetate and acetonitrile.     

毛细管电色谱-质谱联用技术进展

毛细管电色谱-质谱联用技术结合了毛细管电色谱高分离性能和质谱强定性能力的特点，近年来得到较快的发展。本文系统综述了CEC/MS接口技术及在复杂样品分离分析中应用的最新进展。引用文献45篇。     

Quantification of Diaminomaleonitrile Using High Performance Liquid Chromatography with UV and Electrospray Ionization Mass Spectrometric Detection

Abstract

A method was developed to quantify diaminomaleonitrile (DAMN) in complex aqueous matrices using high performance liquid chromatography with UV and electrospray ionization mass spectrometric (ESI-MS) detection. The method is rapid (analytical times <10 min), able to quantify DAMN against complex backgrounds, and achieved with part per billion detection limits. Given the central role of DAMN in generating heterocycles of known biological significance, this study provides a rapid and sensitive method for quantifying DAMN in complex solutions.     

液-质联用研究红豆杉提取物中紫杉烷类化合物

建立了一套利用反相高效液相色谱和大气压化学电离质谱联用技术分析红豆杉提取物中微量紫杉烷类化合物的方法。通过研究已知的10种紫杉烷类化合物的保留时间、质谱特征，初步建立了一个紫杉烷类化合物的数据库，利用这些数据可快速鉴定红豆杉提取物中已知的紫杉烷类化合物，并能够对未知化合物做一定程度的结构分析。这种研究方法同样对其他天然产物特别是微量成分结构分析具有指导作用。     

Combination of Aqueous and Non-Aqueous Capillary Electrophoresis with Electrospray Mass Spectrometry for the Determination of Drug Residues in Water

Summary.  The work presented in this paper deals with the combination of capillary electrophoresis (CE) with electrospray mass spectrometry (MS) for the determination of drug residues in water. CE/MS methods have been developed based on either aqueous or non-aqueous ammonium acetate solutions as the carrier electrolyte for the separation of selected drugs. The different separation conditions were compared in terms of selectivity and detection limits; both aqueous and non-aqueous CE proved to be suitable for the present analytical task, exhibiting detection limits between 3 and 93 μg/dm³ (injected standard concentration) corresponding to concentrations between 5 and 19 ng/dm³ in the sample. A combination of liquid-liquid extraction and solid-phase extraction was investigated for sample pretreatment, yielding enrichment factors of 10000. The applicability of CE/MS was demonstrated for the analysis of several river water samples. Received August 25, 2000. Accepted October 17, 2000     

毛细管电泳-电喷雾质谱联用技术及其在蛋白质分析领域中的应用

综述了毛细管电泳与电喷雾质谱联用的接口技术、分离模式及其在蛋白质分析领域中的应用，特别是毛细管等电聚焦与电喷雾质谱联用在蛋白质组学中研究进展。     

A Chemical Ionization Mass Spectrometric Study of Fluorescamine and Fluorescamine - Amino Acid Derivatives

Abstract

The chemical ionization mass spectra of fluorescamine and fluorescamine - amino acid derivatives have been studied using methane and ammonia as reagent gases. Major ions in the spectra are protonated molecular ions, adduct ions and ions formed by loss of an oxygen atom.

Fluorescamine, 4-phenyl-spiro[furan-2(3H),1′-phthalan]3,3′-dione, is a powerful new fluorogenic reagent for assaying primary amines.¹ and EI² and EI³ mass spectrometric investigations of fluorescamine and its derivatives were carried out. Our present study reports the CI mass spectral analysis of fluorescamine and some of its amino acid derivatives.     

手性整体柱毛细管电色谱法拆分溴氰菊酯对映体

采用一步键合法制备了烯丙基-β-环糊精手性整体柱,将其作为毛细管分离柱,用毛细管电色谱法对溴氰菊酯的对映体进行手性拆分。在优化的试验条件下,乙腈与pH 6.5的5 mmol·L-1磷酸二氢钠溶液以体积比40比60组成的混合溶液作为流动相,运行电压为10 kV,毛细管柱温为20℃,溴氰菊酯的4对对映体在10 min内成功分离。     

Preparation and Porous Property of C14-Monolithic Column for Capillary Electrochromatography

Capillary electrochromatography (CEC) has been performed with a series of C₁₄, methlyacrylamide based monolithic columns. These monoliths with different porosities were prepared by in-situ copolymerization in fused-silica capillaries. The porous properties of monoliths were further observed using scanning electron micrographs (SEM) and measured using a mercury porosimeter. The effect of various alcohols as porogens on porous structural properties and chromatographic behaviors were also investigated. The effects of organic additive, pH value and ionic strength in mobile phase on electroosmosis flow (EOF) and separation were further discussed. Meanwhile, the baseline separation of 6 neutral compounds can be well obtained. In addition, the monolithic column demonstrates the high column efficiency and satisfactory reproducibility.Acknowledgements We gratefully acknowledge the support of the National Natural Science Foundation of China.     

使用含离子涂层柱的毛细管电泳和毛细管电色谱的研究进展

 毛细管电色谱是近年发展起来的高效、高选择性的微分离技术。与一般的毛细管电泳和使用ODS反相填料的毛细管电色谱相比 ,含离子涂层柱的毛细管电泳和毛细管电色谱能提供较大且可控的电渗流 ,便于拓宽分离对象 ,优化分离条件。对使用含离子涂层柱的毛细管电泳和电色谱的特点、发展和应用状况进行了综述。     

Properties and Applications of Mixed Packing Capillary Electrochromatography

Mixed packing capillary electrochromatography (MP CEC) with the stationary phase comprising a physical mixture of strong cation exchange (SCX) phase and octadecysilyl (ODS) phase was developed. With the existence of a sulfonic acid group on the surface of SCX, not only could the electroosmotic flow (EOF) remain high at low pH, but also the hydrophilicity of the stationary phase was increased greatly, leading to broad adaptable ranges of both pH and organic modifier concentration in the mobile phase. At the same time, with the coexistence of C₁₈ on the surface of ODS, both the retention and the resolution of samples were improved. Accordingly, MP CEC combined the advantages of both SCX and ODS columns. Effects of operation parameters on EOF and the capacity factors of solutes as well as the retention mechanism of such a column were studied systematically. In addition, MP CEC columns were used in the analysis of strong polar solutes as well as for the high speed separation of acidic, basic, and neutral compounds in a single run.     

Effects of Blending Bare-Silica and Reversed-Phase on Retention of Neutral Compounds in Capillary Electrochromatography

Most commercially available instruments for capillary electrochromatography (CEC) have a fixed configuration and lack the flexibility to use shorter columns. Applying a blended stationary phase (a phase consisting of a given ratio of bare silica and reversed phase material) can simulate columns of different length in CEC. The goal of this work was to examine the effect of the degree of blending of reversed-phase columns (with bare silica) on the speed of the separation of neutral compounds in CEC. Optimum column packing mixture was determined from the variation of the solute retention factors as a function of the ratios of blending of reversed-phase and bare silica. By adjusting the column composition, solute retention factors and the analysis run time were halved when compared to a pure reversed-phase column of the same length. Stationary phase blending can be considered as an additional parameter to mobile phase variation, column temperature and applied electric field for the optimization of selectivity and analysis time. By adjusting the stationary phase composition, mobile phase composition, column temperature and applied electric field, the analysis run time of neutral components was decreased more than 75% when compared to a separation obtained on neat reversed-phase column of the same dimensions. The linear dependence of the retention factors as a function of the blend ratio (reversed phase/bare silica) offers a framework for designing a “blended” packed capillary column for CEC separations.     

氟西汀和西替利嗪对映体的双动态吸附毛细管电色谱手性分离

建立了以海美溴铵（hexadimethrine bromide,HDB)为阳离子表面活性剂，并以磺化β－环糊精（SO3－β－CD）为手性选择剂的双动态吸附毛细管电色谱；考察了背景电解质pH和浓度、环糊精种类和浓度对分离的影响，对分离条件进行了优化，并对手性识别机理进行了探讨；实验结果表明在含0．1g/L HDB和20mmol/L SO3-β-CD的20mmol/L Tris-H3PO4(pH3.00)的体系中，氟西汀和西替利嗪对映体在较短的时间内达到良好分离。     

金纳米粒子修饰毛细管硅胶整体柱的制备及其电色谱性能研究

通过毛细管硅胶整体柱表面修饰十八烷基硫醇金纳米粒子,制备了一种新型毛细管电色谱固定相.制备金纳米粒子修饰整体柱时,采用溶胶-凝胶法制备毛细管硅胶整体柱,并在其表面化学修饰3-巯基丙基三甲氧基硅烷;通过巯基基团固载金纳米粒子于整体柱上,再共价键合十八烷基硫醇于金纳米粒子表面.以甲苯为探针,对理论塔板高度与流动相线速度之间...     

丁基胺丙基硅胶毛细管整体柱的制备及其电色谱性能研究

采用溶胶-凝胶技术制备了丁基胺丙基硅胶毛细管整体柱,此整体固定相表面同时含有能产生阳极的电渗流的仲胺官能团和产生疏水作用的正丁基和丙基官能团。对所制备的整体柱电色谱性能进行了详细的表征和分析。考察了流动相pH值对电渗流的影响;对烷基苯同系物、有机酸酸性化合物和苯胺类碱性化合物保留行为进行了研究,并对其可能的保留机理进行了探讨。实验结果表明,对于中性化合物的保留机理主要基于反相作用;而对于酸性化合物的保留行为则是基于混合模式作用机理,即除了电泳作用外,还包括阴离子交换和疏水作用。碱性化合物在丁基胺丙基硅胶毛细管整体柱上的峰形较好,没有明显的峰拖尾现象。     

十八烷基改性纳米二氧化硅涂层毛细管柱在毛细管电色谱中的应用

采用液相沉积技术制备了纳米二氧化硅涂层毛细管,经十八烷基改性,将其作为开管毛细管电色谱(OTCEC)分离介质。研究了该涂层毛细管的电渗流行为,考察了烷基苯和多环芳烃的毛细管电色谱分离性能。结果表明,该涂层固定相对这些化合物表现出较强的疏水作用;增加液相沉积涂层次数有利于增加溶质的保留因子,四种多环芳烃和四种苯同系物在该柱上可实现基线分离。此外,该涂层制备简单、重现性好,并在应用中表现出较高的稳定性。     

一些烷氧基亚甲基二苯胂基二茂铁衍生物的质谱分析

对６个新的烷氧基亚甲基二苯胂基二茂铁衍生物进行质谱分析研究，在它们的电子轰击电离质谱中显现了强的分子离子峰和表征主体结构的一系列特征峰。通过磁场／静电场联动扫描和精确质量的测定探索了这类化合物的质谱裂解规律。     

质谱离子源技术用于电化学反应机理研究的进展

电化学反应是连续的动态变化过程,伴随着瞬时中间体和复杂结构物质的产生,因此,精确而有效地捕捉反应过程中的一系列产物,有助于准确推导其电化学反应机理,进而优化反应条件,提高反应效率.目前,主流的电化学在线监测技术包括光谱法、循环伏安法和线性极化曲线等,这些方法能够胜任反应过程中大部分物质的结构及组成变化检测,然而,为了更加系统和精确地掌握电化学反应过程中所有产物的信息,仍需进一步拓展实时、原位反应监测技术.质谱具有灵敏度高、选择性好、分析速度快、可以结构解析等特点,是一种理想的电化学反应研究手段.近年来,采用质谱法研究电化学反应机理的报道越来越多,尤其是采用以电喷雾离子源(Electrospray Ionization,ESI)及其衍生离子源为代表的常压离子源对电化学反应过程进行实时、原位监测已经成为研究热点.本综述主要介绍了近期发表的电化学-质谱联用技术,详细描述了其针对不同类型电化学反应监测要求而设计和开发的电化学离子源装置.     

反相毛细管电色谱中中性化合物的保留及有机改性剂对其保留值的影响

以硫脲作为电渗流标记物测定的死时间和以苯同系物线性回归方法测定的死时间为基础，将液相色谱中溶质保留值方程应用到电色谱中，得到了容量因子与二元流动相体系中有机改性剂含量之间的关系曲线；通过实验数据说明了一些极性的电中性化合物在电场作用下也会发生迁移而引起保留值的变化，且这种变化还受有机改性剂含量的影响。     

血卟啉及其金属衍生物的化学电离质谱

本研究采用直接曝热技术，分别以氢气和甲烷为反应气，测定了１０个血卟啉衍生物和１３个金属血卟啉衍生物的正、负离子解吸化学电离质谱，探讨了各种化学电离质谱法在结构测定中的应用。