成像检测在DNA毛细管电泳中的应用

本文研究了成像检测方式以及阵列检测器在DNA毛细管电泳的荧光检测中的应用,目的在于减小检测过程引起的样品区带增宽,提高DNA毛细管电泳的分辨率和分离速度。依据分离度理论以及模拟计算结果,归纳了检测宽度的影响规律,指出减小检测宽度对于高效分离,特别是高速微流控系统电泳分离的重要性。实验测量并比较了成像检测与传统光强检测的结果。提出阵列检测器的信号增强方法,并进行了模拟验证。研究表明,成像检测可显著减小毛细管电泳的检测宽度,提高分离效率和分离速度。     

Pulsed UV Laser-Induced Stationary Capillary Vibration for Highly Sensitive and Direct Detection of Capillary Electrophoresis

A stationary wave of the capillary vibration effect was successfully induced by a series of short laser pulses. This wave could be applied to highly sensitive detection of capillary electrophoresis as well as the already reported capillary vibration induced by an intensity-modulated CW laser (CVL effect). Generally, pulses with much shorter width than the period of the natural frequency of the vibrating system cannot induce a standing vibration. However, utilizing the time constant of CVL determined by heat dissipation time, we found conditions which could induce a stable stationary wave of the capillary by a series of nanosecond light pulses. We used the KrF excimer laser operated at 248 nm with a pulse width of 60 ns and output of ～10 μJ/pulse as the CVL excitation source and applied it to highly sensitive detection of nonderivatized amino acids at the femtomole level. The sensitivity was at least 2 orders of magnitude superior to that of a commercially available UV absorbance detector. This technique extends the CVL's spectral regions. For example, in the UV region, where many biological materials have significant absorption bands, this technique will extend analytical applications in capillary electrophoresis by eliminating the need for a derivatization process.     

表面贴附微透镜阵列的OLED诱导荧光检测系统

为进一步减小光源的体积、简化光路系统结构,消除毛细管电泳芯片诱导荧光检测系统中激发光源的反射光和杂散光的干扰,设计并建立了垂直层叠结构的有机发光二极管诱导荧光检测系统。针对有机发光二极管器件发光强度较低的问题,采用在器件的玻璃基底表面贴附微透镜阵列薄膜的方法,提高了入射光的强度。在对CCD积分时间、PDMS微透镜直径及两偏振片间的偏振角度等参数进行优化之后,利用检测系统实现了罗丹明B样品溶液的毛细管电泳分离。     

毛细管电泳非接触电导检测器的研制

非接触电导检测法已经成为毛细管电泳芯片中一种通用的物质分离检测方法．本文提出了一种微型化的电容耦合非接触电导分析系统,采用新颖的三明治电极结构减小了电极之间的寄生电容．这种电极结构能够有效地减小电极的长度,克服了非接触电导检测中电极易于折断的缺点．当采用电极宽度1mm、电极间距1mm、MES／His缓冲溶液浓度为20mmol／L和激励电压20Vpp、90kHz的条件时,检测器具有最好的分离效果．在最佳的分离效果,实现了1mmol／L的K^＋和Mg^2＋混合无机阳离子的分离检测．     

单片集成毛细管区带电泳分析器的进样

探讨了玻璃基片上毛细管区带电泳集成系统的进样及其对分离效率的影响 ,在本实验模型中 ,分离管道长 4cm ,10 0V/cm电场下的理论塔板数可至 4 50 0 0。     

Integrated Capillary Electrophoresis/Electrochemical Detection with Metal Film Electrodes Directly Deposited onto the Capillary Tip

The practical application of electrochemical detection in capillary electrophoresis has been hampered by irreproducibility and inconvenience related to capillary/electrode alignment. In order to eliminate these problems, a simple, flexible method by which the capillary and the working electrode were integrated into a single operational unit was devised and evaluated. The electrodes were formed by sputtering a thin conductive layer of Au or Pt onto the exit tip of the capillary. Depending on the size of the capillary used (i.e., both inner and outer diameters), Au on-capillary electrodes (OCEs) gave detection limits at the micromolar level and slightly below for the test analytes dopamine and catechol. More important, operation of the OCEs required no alignment procedures beyond immersion in the CE buffer reservoir/detector cell. OCEs used in this manner exhibited relative standard deviations of 2-4% for repeated injections even if removed from solution between runs. Finally, the Au and Pt OCEs could themselves be modified further by conventional electrochemical procedures. Here, Cu OCEs, formed by electrodeposition onto Au, were used to detect carbohydrate compounds; and an enzyme OCE, formed by adsorption of glucose oxidase onto Pt, was used to detect glucose.     

毛细管电泳电化学检测水果中的抗坏血酸

利用毛细管电泳电化学检测法检测了抗坏血酸,考察了缓冲液的pH值、缓冲液浓度、分离电压、检测电势等实验参数对检测的影响。在最佳实验条件下,检测抗坏血酸的浓度范围是(1.0×10-5-5.0×10-3)mol.L-1,线性回归系数为0.9995,浓度检测限(S/N=3)为3.7×10-6mol.L-1,并以此方法检测了新鲜水果中的抗坏血酸的含量。     

芯片毛细管电泳技术的应用与进展

介绍了目前芯片毛细管电泳的主要分离技术:芯片毛细管区带电泳、芯片毛细管凝胶电泳、芯片胶束电动色谱、芯片毛细管电色谱及多相层流无膜扩散分离.芯片毛细管电泳的研究已经取得了很大的进展,研制出了多种微型化、集成化的芯片,多种分离技术在芯片上的开发应用,显示出芯片毛细管电泳技术在众多分析领域会有广阔的发展前景.     

毛细管电泳测定大黄素主成分的含量

以熔融石英毛细管柱(60.2 cm×50μm,有效长度50 cm)为分离柱,70 mmol/L Na2B4O7、70 mmol/LNa2CO3和80 mmol/L羟丙基-β-环糊精(pH 9.7)为分离缓冲溶液,测定了纯化后的大黄素的主成分含量为98.50%,方法精密度为0.1%(n=9),并与高效液相色谱法的测定结果进行了比较,二者无显著性差异.     

Focusing and Mobilization of Bacteria in Capillary Electrophoresis

An isotachophoretic method has been developed for mobilizing and focusing bacteria. This allows quantification and detection of bacteria in a narrow zone. Very good linearity was obtained for Micrococcus lysodeikticus (also called Micrococcus luteus, studied as a model of Gram+ bacteria) in the range of 0.4 × 10(8) cells/mL to 2.9 × 10(8) cells/mL, with correlation coefficients for peak height and peak area as a function of cell concentration of 0.999 and 0.998, respectively. This method is usable on both bare and hydroxypropyl cellulose-coated fused silica capillaries. The best results were obtained using 13.6 mM Tris, 150 mM boric acid as terminating electrolyte, and 4.5 mM Tris, 50 mM boric acid, and 3.31 mM HCl as leading electrolyte. With a 33.5 cm ×100 μm i.d. capillary, short migration times were obtained while maintaining very low electrical current in order to minimize any Joule heating and lysis of the bacteria. A UV area imaging detector (ActiPix D100, Paraytec) was used with a 109 cm × 100 μm i.d. capillary having three loops and four detection windows to monitor the migration behavior of M. luteus and to show the stability of the zone of the focused bacteria along the capillary. Similar results were obtained for Erwinia carotovora (a model of Gram- bacteria), and for Enterobacter cloacae and Vibrio splendidus.     

毛细管电泳法分析盐酸头孢吡肟中N-甲基吡咯烷含量

建立了一种毛细管电泳间接紫外检测注射用盐酸头孢吡肟中的N-甲基吡咯烷(NMP)含量的方法,讨论了检测波长、电压、进样时间、缓冲溶液的pH值等因素对盐酸头孢吡肟中NMP的影响,获得了优化的分离条件.结果表明,以含0.01 mol/L咪唑和1 mol/L的醋酸(pH=4.7)溶液为背景电解质.在电压为3.00kV,检测波长...     

High-Resolution Studies of Hyaluronic Acid Mixtures through Capillary Gel Electrophoresis

Hyaluronic acid is a negatively charged polysaccharide with a high degree of polydispersity that makes the separation of its oligomers extremely difficult. Through the use of columns filled with a highly viscous polyacrylamide matrix, the unit resolution of hyaluronate oligomers could be achieved, up to at least 80 kDa of mass, through capillary electrophoresis. As analytical application examples, the fractions of enzymatically or ultrasonically degraded hyaluronates were monitored through this method. Because of the very high resolving power, peaks additional to the regular oligomers can be observed that are assumed to be conformers of this regular, unbranched biopolymer.     

毛细管区带电泳分离甲酚异构体的研究

本文系统地研究了邻、间、对甲酚三种异构体在毛细管区带电泳中的迁移行为。通过实验研究讨论了缓冲溶液类型、缓冲溶液的pH值、缓冲溶液的浓度和添加剂等因素对三种异构体分离的影响,获得了优化的分离条件。结果表明,在使用未涂层石英毛细管柱(50μm×50cm,有效长度为45 cm),检测波长225 nm,磷酸盐-环糊精-硼砂缓冲溶液浓度30 mmol/L,缓冲液pH值为11.60,分离电压为15 kV的条件下,甲酚三种异构体得到基线分离。     

Peer Reviewed: Orthogonal-Injection TOFMS for Analyzing Biomolecules

Orthogonal injection provides a high- efficiency interface for transferring ions from a continuous beam to a pulsed mode and makes it easier to obtain high resolution.     

Complexation between Amylodextrin Oligomers and Selected Pharmaceuticals Measured through Capillary Electrophoresis

The amylodextrin oligomers, tagged fluorescently at their reducing ends for laser fluorescence detection, were used as model solutes to investigate certain carbohydrate-drug interactions through capillary electrophoresis. The separation patterns of some oligomers were found to be altered significantly by the presence of selected pharmaceuticals used as buffer additives. The selectivity of complexation at a particular size of an oligomer could be judged from alterations in migration times and peak shapes. The formation of complex was influenced substantially by solutes' chemical environment (pH, ionic strength, and the nature and concentration of organic additives). The chemical nature of the guest molecules also played an important role in complexation. Using amylodextrins as chiral selectors, enantiomeric resolution of several pharmaceuticals was achieved electrophoretically. The conclusions drawn from electrophoretic data were found to be in close agreement with the results of a (13)C NMR study.     

Enhancement of Separation Efficiency in Capillary Electrophoresis by Electrostacking without Liquid Contact

Quantitative reproducibility and separation efficiency in high-performance capillary electrophoresis is often limited by the reproducibility and the nature of the sample introduction procedure. This is particularly true where electrostacking is involved, whether such is deliberately carried out or happens automatically with the choice of ionic strength of the running electrolyte. Extraneous dispersion frequently originates in the act of sample introduction, for example, from the shock of the capillary entering a sample vial or a sample-filled capillary entering the carrier electrolyte source vial. A method based on the stacking of the sample constituents, before the capillary actually contacts the liquid in a vial, can reduce this problem. This technique can be utilized for the preconcentration of sample constituents and to improve separation efficiency by reducing dispersion. In favorable cases, plate counts can increase by as much as 160%, approaching theoretical diffusion-limited efficiencies.     

高效毛细管电泳/电导检测法测定饮用水中的阴离子

本实验采用四乙烯五胺作为毛细管电泳的电渗流抑制剂,以10mmol/L Tris(三羟甲基氨基甲烷)+10mmol/L H3BO3(硼酸)+0.2mmol/L EDTA(乙二胺四乙酸)+0.2%(V/V)四乙烯五胺为电泳运行液,负高压分离(-15kV),电导检测,对饮用水中的Cl-、NO3-、SO42-三种阴离子进行了直接分离测定,并考察了分离电压,pH值,电解质溶液的组成及浓度,电渗流抑制剂,有机添加剂组成等对分离的影响。建立高效、快速的饮用水无机阴离子高效毛细管电泳/电导检测的分析方法。     

Simultaneous Determination of Ionization Constants and Isoelectric Points of 12 Hydroxy-s-Triazines by Capillary Zone Electrophoresis and Capillary Isoelectric Focusing

Capillary zone electrophoresis (CZE) was used to separate and determine simultaneously the pK(1), pK(2), and pI values of 12 environmentally relevant hydroxytriazines (hydroxymetabolites of atrazine, terbuthylazine, simazine, and propazine and four (arylamino)-s-triazines) and observe the effects of the alkylamino and arylamino substituents on the measured values. Capillary isoelectric focusing (CIEF) methods were developed to measure the pI of these compounds and compare those values with the CZE-measured pI's. CZE and CIEF can provide accurate pK and pI values reasonably fast, and pI values measured by the two techniques agree. Knowledge of the pK and pI values of hydroxytriazines is important for an understanding of the binding mechanisms of these molecules in environmental matrices. Because the hydroxytriazines may exist as a myriad of species [Formula: see text] neutral, charged, zwitterionic, and keto-enol tautomeric [Formula: see text] depending on structure and pH, we briefly addressed the existence of these species relative to their electrophoretic analysis.     

毛细管区带电泳法测定饮料中苯甲酸和山梨酸

应用毛细管区带电泳技术,建立了饮料中苯甲酸、山梨酸测定方法,并通过对电泳缓冲溶液浓度及pH、进样溶液pH等电泳条件的优化,提高了方法的灵敏度。苯甲酸检出限0.4mg/L,山梨酸检出限0.2mg/L,本方法的回收率在96％～102％之间。该方法具有前处理简便、快速、准确等特点,饮料只需用缓冲液稀释即可直接进样,3分钟内出结果,重现性好。     

Characterization of Nonbonded Poly(ethylene oxide) Coating for Capillary Electrophoresis via Continuous Monitoring of Electroosmotic Flow

We examined changes in a poly(ethylene oxide) (PEO) coating by continuously monitoring the electroosmotic flow (EOF) in a fused-silica capillary during electrophoresis. An imaging CCD camera was used to follow the motion of a fluorescent neutral marker zone along the length of the capillary. The PEO coating was shown to reduce the velocity of EOF by more than 1 order of magnitude compared to a bare capillary at pH 7.0. However, it did not reduce EOF efficiently at pH 8.2. The coating protocol was important, especially at an intermediate pH of 7.7. Capillary reconditioning with an acidified solution of PEO was necessary in order to create a stable and efficient coating. In all cases we observed a gradual increase of EOF during extended runs, suggesting that the coating is slowly being degraded. The increase of pH in the cathodic (detection-end) buffer reservoir beyond pH ～8.0, e.g., as a result of electrolysis, had a large impact on the stability of the coating. This phenomenon may be used for the efficient and fast regeneration of the column surface and provides a simpler and more reliable alternative to pressure flushing of the capillary.