非水介质毛细管电泳电导检测罗红霉素及其制剂

采用甲醇为分离介质，三(羟甲基)氨基甲烷-硼酸(Tris—H3BO3)为支持电解质，采用负高压，使用电导检测，对罗红霉素及其制剂进行了毛细管电泳分离检测，对电泳介质的种类、浓度、表观pH、以及操作电压和进样时问对分离的影响进行了研讨，在选定的条件下，罗红霉素的线性范围为19．0—142．0mg/L，检出限为0．8mg/L(S／N≥3)，峰面积的相对标准偏差RSD(n=6)为4．3％。3种供试品中罗红霉素的平均加标回收率分别为97．7％、94．8％、93．6％。     

Contactless conductivity detection for microfluidics: designs and applications

Different methods for construction of contactless conductivity detectors (CCD) for microchip electrophoresis device are described in this review. This includes three main schemes of CCD for microchips, such as (i) the detection electrodes are placed along the microchannel from outside of the microchip and they are insulated from the channel by the cover lid of microchip device; (ii) the electrodes are placed across of the microchannel in the same plane and they are insulated by thin separation channel walls and (iii) electrodes are buried in widened part of microchannel and they are insulated from solution by ultrathin layer of silicon carbide. Specific issues related to the CCD on microfluidics are discussed, such as an influence of shape and magnitude of ac voltage and placement of electrodes and their insulation. Various applications for security, pharmacological, bioassays and food analysis purposes are described.     

Determination of heavy metal ions by microchip capillary electrophoresis coupled with contactless conductivity detection

An integrated detection circuitry based on a lock-in amplifier was designed for contactless conductivity determination of heavy metals. Combined with a simple-structure electrophoresis microchip, the detection system is successfully utilized for the separation and determination of various heavy metals. The influences of the running buffer and detection conditions on the response of the detector have been investigated. Six millimole 2-morpholinoethanesulfonic acid + histidine were selected as buffer for its stable baseline and high sensitivity. The best signals were recorded with a frequency of 38 kHz and 20 V(pp). The results showed that Mn(2+), Cd(2+), Co(2+), and Cu(2+) can be successfully separated and detected within 100 s by our system. The detection limits for five heavy metals (Mn(2+), Pb(2+), Cd(2+), Co(2+), and Cu(2+)) were determined to range from about 0.7 to 5.4 μM. This microchip system performs a crucial step toward the realization of a simple, inexpensive, and portable analytical device for metal analysis.     

Contactless Conductivity Detection in Capillary Electrophoresis: A Review

The popularity of contactless conductivity detection in capillary electrophoresis has been growing steadily over the last few years. Improvements have been made in the design of the detector in order to facilitate its handling, to allow easy incorporation into available instruments or to achieve higher sensitivity. The understanding of its fundamental working principles has been advanced and the detection approach has also been transferred to lab‐on‐chip devices. The range of applications has been extended greatly from the initial work on small inorganic ions to include organic species and biomolecules. Concurrent determination of cations and anions by dual injection from opposite ends has been demonstrated as well as sample introduction by using flow‐injection systems for easy automation of the process.     

基于无接触电导检测和流动注射进样的微型毛细管电泳系统

毛细管电泳(CE)电导检测(CD)是相对较灵敏和仪器结构简单的一项溶液分析技术,尤其是对于无生色团的无机离子分析更具有突出优势.然而,目前众多商品CE仪器并不配置CD检测器,这极大地限制了该项技术的发展.     

非水介质毛细管电泳电导法检测盐酸胺碘酮

采用非水介质毛细管电泳电导检测法对盐酸胺碘酮进行检测。探讨了缓冲溶液的种类、pH和浓度、分离电压、进样时间、进样高度等因素对检测效果的影响,建立了测定盐酸胺碘酮的新方法。用乙醇作为非水介质,在30mmol L三羟甲基氨基甲烷 15mmol L柠檬酸(pH6.90)运行缓冲溶液中,盐酸胺碘酮在5～200mg L范围内的线性回归方程为y=74.94x-7.83,r=0 999。检出限(S N=3)为0.5mg L,样品回收率为98.9%。适用于含盐酸胺碘酮的药剂的分析。     

毛细管电泳及芯片毛细管电泳的电容耦合非接触电导检测

综述了毛细管电泳(CE)及芯片毛细管电泳(MCE)的电容耦合非接触电导检测(Capacitively Coupled Contactless Conductivity detection,C4D)的研究状况;并分别对其装置、检测的影响因素及其应用进行了评述。引用文献81篇。     

Contactless conductivity detector array for capillary electrophoresis

A CE system featuring an array of 16 contactless conductivity detectors was constructed. The detectors were arranged along 70 cm length of a capillary with 100 cm total length and allow the monitoring of separation processes. As the detectors cannot be accommodated on a conventional commercial instrument, a purpose built set‐up employing a sequential injection manifold had to be employed for automation of the fluid handling. Conductivity measurements can be considered universal for electrophoresis and thus any changes in ionic composition can be monitored. The progress of the separation of Na⁺ and K⁺ is demonstrated. The potential of the system to the study of processes in CZE is shown in two examples. The first demonstrates the differences in the developments of peaks originating from a sample plug with a purely aqueous background to that of a plug containing the analyte ions in the buffer. The second example visualizes the opposite migration of cations and anions from a sample plug that had been placed in the middle of the capillary.     

A review of the recent achievements in capacitively coupled contactless conductivity detection

Capacitively coupled contactless conductivity detection (C⁴D) in the axial electrode configuration was introduced in 1998 as a quantification method for capillary electrophoresis. Its universality allows the detection of small inorganic ions as well as organic and biochemical species. Due to its robustness, minimal maintenance demands and low cost the popularity of this detector has been steadily growing. Applications have recently also been extended to other analytical methods such as ion chromatography, high-performance liquid chromatography and flow-injection analysis. C⁴D has also found use for detection on electrophoresis based lab-on-chip devices. Theoretical aspects of C⁴D in both the capillary and microchip electrophoresis format have been comprehensively investigated. Commercial devices are now available and the method can be considered a mature detection technique. In this article, the achievements in C⁴D for the time period between September 2004 and August 2007 are reviewed.     

A novel microchip based on indium tin oxide coated glass for contactless conductivity detection

A microfluidic chip manufactured from glass substrate and indium tin oxide (ITO) coated glass use for contactless conductivity detection was developed. The detecting electrodes were fabricated by screen-printing and chemical etching methods using an ITO-coated glass wafer. Then, the glass substrate containing separation channels was bonded with the bare side of the processed ITO-coated glass, thus producing an electrophoresis chip integrated with contactless conductivity detector. The prepared microchip displayed considerable stability and reproducibility. Sensitive response was obtained at optimal conditions (including the gap between electrodes, excitation frequency, and excitation voltage). The feasibility of this microfluidic device was examined by detection of inorganic ions, and further demonstrated by the quantification of aminopyrine and caffeine in a compound pharmaceutical. The two ingredients can be completely separated within 1 min. The detection limits were 8 μg mL⁻¹ and 3 μg mL⁻¹, respectively; with the correlation coefficient of 0.996-0.998 in the linear range from 10 μg mL⁻¹ to 800 μg mL⁻¹. The results have showed that the present method is sensitive, reliable and fast.     

Light-scattering and turbidimetric detection of silica colloids in size-exclusion chromatography

Silica colloids were separated by size-exclusion chromatography and monitored by fluorimetric and UV detection. In the former means of detection, silica colloids were visualized by light-scattering. The signal intensity based on the light scattering increased with increasing size of the silica colloids. The maximum intensity was observed at excitation wavelengths around 270–290nm. In UV detection, silica colloids were visualized based on turbidimetry, and the signal intensity also increased with increasing size of the silica colloids and with decreasing detection wavelength. The signal intensities for both light-scattering and turbidimetric detection were a linear function of the concentration of the silica colloids. The detection limit at S/N = 3 for 78-nm colloids was 0.06 ppm for light-scattering detection whereas the LOD was 2.3 ppm for UV detection. Effects of mobile phase conditions and flow rate on resolution and peak shape were examined. Use of phosphate buffer allowed the separation of silica colloids of different sizes in size-exclusion chromatography.     

Capacitively coupled contactless conductivity detection with dual top–bottom cell configuration for microchip electrophoresis

An optimized capacitively coupled contactless conductivity detector for microchip electophoresis is presented. The detector consists of a pair of top–bottom excitation electrodes and a pair of pickup electrodes disposed onto a very thin plastic microfluidic chip. The detection cell formed by the electrodes is completely encased and shielded in a metal housing. These approaches allow for the enhancement of signal coupling and extraction from the detection cell that result in an improved signal‐to‐noise‐ratio and detection sensitivity. The improved detector performance is illustrated by the electrophoretic separation of six cations (NH, K⁺, Ca²⁺, Na⁺, Mg²⁺, Li⁺) with a detection limit of approximately 0.3 μM and the analysis of the anions (Br^?, Cl^?, NO, NO, SO, F^?) with a detection limit of about 0.15 μM. These LODs are significantly improved compared with previous reports using the conventional top–top electrode geometry. The developed system was applied to the analysis of ions in bottled drinking water samples.     

Evaluation of the detection of biomolecules in capillary electrophoresis by contactless conductivity measurement

The sensitivity of contactless conductivity detection to amino acids, peptides and proteins in CE was studied for BGE solutions of different pH values. The LOD and analytical characteristics were compared for acidic and basic conditions and better results were in most cases found for buffers of low pH values. Linear dynamic ranges varied between two orders of magnitude for amino acids and peptides and three orders of magnitude for larger proteins. The concentration detection limits were found to be between 1.2 and 7.5 microM for the amino acids tested and for the larger molecules they varied between 2.6 microM for leucine enkephalin and 0.2 microM for HSA when using a buffer at pH 2.1.     

微芯片毛细管电泳快速测定加替沙星注射液中加替沙星的含量

研究了用微芯片毛细管电泳非接触电导检测系统快速测定加替沙星注射液中加替沙星的方法。对缓冲液的类型、浓度、分离电压以及进样时间等因素进行了优化。最佳条件为:缓冲液5.0 mmol/L HAc,分离电压2.0 kV,进样时间15.0 s。在该条件下,可在1.0 min内实现加替沙星的快速含量测定。线性范围为4.0～150μg/mL,检出限为1.0μg/mL,加标回收率为95.7%～101%,可成功测定注射液中加替沙星的含量。     

Analysis of phenolic acids by non-aqueous capillary electrophoresis after electrokinetic supercharging

Electrokinetic supercharging (EKS), a new and powerful on-line preconcentration method for capillary electrophoresis, was utilized in non-aqueous capillary electrophoresis (NACE) to enhance the sensitivity of phenolic acids. The buffer acidity and concentration, leader and terminator length and electrokinetic injection time were optimised, with the optimum conditions being: a background electrolyte of 40 mM Tris-acetic acid (pH 7.9), hydrodynamic injection of 50 mM ammonium chloride (22 s, 0.5 psi) as leader, electrokinetic injection of the sample (180 s, -10 kV), hydrodynamic injection of 20 mM CHES (32 s, 0.5 psi) as terminator, before application of the separation voltage (-25 kV). Under these conditions the sensitivity was enhanced between 1333 and 3440 times when compared to a normal hydrodynamic injection with the sample volume <3% of the capillary volume. Detection limits for the seven phenolic acids were in the range of 0.22-0.51 ng/mL and EKS was found to be 3.6-7.9 times more sensitive than large-volume sample stacking and anion selective exhaustive injection for the same seven phenolic acids.     

反向毛细管电泳高频电导法测定牛黄中的胆酸

建立了毛细管电泳高频电导法快速简便测定牛黄粉中胆酸的新方法.考察了电泳介质的种类、浓度、 pH值以及操作电压和进样时间对分离检测的影响.缓冲液为0.5 mmol/L Na3PO4 2 mmol/L Na2HPO4 0.2 mmol/L CTAB(pH 11.7), 分离电压为 -15 kV时可实现较好的分离和检测.胆酸的线性范围为75～200 μg/mL, 检出限为0.1 μg/mL.线性方程为y=0.6054ρ-4.14991, r=0.953.回收率为100.9%, RSD(n=5)=2.1%.     

非水介质毛细管电泳电导检测舒血宁片中槲皮素含量

以甲醇：水＝70：30的体系为分离介质，柠檬酸－三（羟甲基）氨基甲烷（Citric acid-Tris)为支持电解质，使用电导检测，对槲皮素及其制剂舒血宁片进行了毛细管电泳分离检测，对电泳介质的种类、浓度、表观pH值以及操作电压和进样时间对分离的影响进行了研讨，并对分离检测机理进行了探讨。建立的测定槲皮素的方法的线性范围为：8．0－160．0mg/L；峰面积的RSD（n=6)为1．7％，检出限为1．0mg/L；样品加标回收率为92．8％－98．2％。     

Contactless conductivity detection for analytical techniques: Developments from 2016 to 2018

The publications concerning capacitively coupled contactless conductivity detection for the 2‐year period from mid‐2016 to mid‐2018 are covered in this update to the earlier reviews of the series. Relatively few reports on fundamental investigations or new designs have appeared in the literature in this time interval, but the development of new applications with the detection method has continued strongly. Most often, contactless conductivity measurements have been employed for the detection of inorganic or small organic ions in conventional capillary electrophoresis, less often in microchip electrophoresis. A number of other uses, such as detection in chromatography or the gauging of bubbles in streams have also been reported.     

毛细管电泳高频电导法测定苦参中的苦参碱和氧化苦参碱

建立了用毛细管电泳高频电导法测定苦参药材中苦参碱和氧化苦参碱的方法。对电泳介质的种类、浓度、pH值以及操作电压和进样时间对分离检测的影响进行了研究。缓冲液为2.0mmol LNa2HPO4 1.0mmol LH3PO4 体积分数为25%乙醇(pH6.0),分离电压为16.0kV时可实现较好的分离与检测。苦参碱和氧化苦参碱的线性范围为:25.0～1.00×103μg mL(相关系数分别为0 987和0.999);RSD(n=6)分别为:2.1%和0.70%;检出限分别为10.0和5.00μg mL;回收率分别为92.7%～99.1%和100%～102%。     

Determination of textile dyes by means of non-aqueous capillary electrophoresis with electrochemical detection

Eight textile dye compounds including five cationic dyes, namely, basic blue 41, basic blue 9, basic green 4, basic violet 16 and basic violet 3, and three anionic dyes, acid green 25, acid red 1 and acid blue 324, were separated and detected by non-aqueous capillary electrophoresis (NACE) with electrochemical detection. Simultaneous separations of acid and basic dyes were performed using an acetonitrile-based buffer. Particular attention was paid to the determination of basic textile dyes. The optimized electrophoresis buffer for the separation of basic dyes was a solvent mixture of acetonitrile/methanol (75:25, v/v) containing 1 M acetic acid and 10 mM sodium acetate. The limits of detection for the basic dyes were in the range of 0.1–0.7 μg mL⁻¹. An appropriate solid-phase extraction procedure was developed for the pre-treatment of aqueous samples with different matrices. This analytical approach was successfully applied to various water samples including river and lake water which were spiked with textile dyes.