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CE System (ce + system)
Selected AbstractsSimultaneous determination of nine endogenous steroids in human urine by polymeric-mixed micelle capillary electrophoresisELECTROPHORESIS, Issue 19 2010Sabrina Flor Abstract A new CE system based on the use of polymeric-mixed micelles (cholic acid, SDS and the poloxamine Tetronic® 1107) was developed for the simultaneous determination of nine steroids in human urine. This method allows the baseline separation and quantitation of cortisol, androstenedione, estriol, dehydroepiandrosterone sulfate, testosterone, dehydroepiandrosterone, estrone, progesterone and estradiol in less than 25,min showing to be sensitive enough to detect low concentrations of these steroids in urine samples (5,45,ng/mL). The optimized electrophoretic conditions were performed using a 50,cm×75,,m capillary, 18,kV, 25°C, with 44,mM cholic acid, 10,mM SDS, 0.05%,w/v tetronic® 1107, 2.5%,v/v methanol, 2.5%,v/v tetrahydrofuran in 5,mM borate , 5,mM phosphate buffer (pH=8.0) as a background electrolyte and a dual 210/254 UV-detection. The method can simultaneously determine 0.1,120,,g/mL, which corresponds to 5,6000,ng/mL of steroids in 2,mL urine. The recoveries ranged between 82.4 and 101.5%. Due to its simplicity, speed, accuracy and reliability, the proposed method could be a potential alternative to the traditional methodologies used with clinical purposes. [source] Electromigration diffusivity spectrometry: A way for simultaneous determination of diffusion coefficients from mixed samplesELECTROPHORESIS, Issue 17 2010Suhua Yang Abstract A novel method was proposed for simultaneous measurement of diffusion coefficients, (D), from mixed samples by electrophoresis and termed electromigration-based diffusivity spectrometry. After theoretical treatment, D- equation for practical use has been deduced. With a modified CE system built in laboratory, electromigration-based diffusivity spectrometry has been realized and validated to suit for fast and accurate determination of diffusivities of mixed aromatic amino acids, phenols and aromatic organic acid, giving diffusivity spectra by peak area versus D, much similar to mass spectra. The precision of the measurement was found to critically depend on pH value of running buffer, which should be so selected that the analytes and internal standards could be charged at above 0.5e. The standards have to be selected at an electric flux far from each other and from analytes. In these cases, sample and running buffer concentrations, voltage and system temperature were found to have only negligible impact on the determination. In our test, the obtained measuring precision was generally kept within 1% for five runs, and the measured values of D agreed well with those from literature, with a deviation of less than 2.2% after the right use of calibration standards. [source] Universal multiplex PCR and CE for quantification of SMN1/SMN2 genes in spinal muscular atrophyELECTROPHORESIS, Issue 7 2009Chun-Chi Wang Abstract We established a universal multiplex PCR and CE to calculate the copy number of survival motor neuron (SMN1 and SMN2) genes for clinical screening of spinal muscular atrophy (SMA). In this study, one universal fluorescent primer was designed and applied for multiplex PCR of SMN1, SMN2 and two internal standards (CYBB and KRIT1). These amplicons were separated by conformation sensitive CE. Mixture of hydroxyethyl cellulose and hydroxypropyl cellulose were used in this CE system. Our method provided the potential to separate two 390-bp PCR products that differ in a single nucleotide. Differentiation and quantification of SMN1 and SMN2 are essential for clinical screening of SMA patients and carriers. The DNA samples included 22 SMA patients, 45 parents of SMA patients (obligatory carriers) and 217 controls. For evaluating accuracy, those 284 samples were blind-analyzed by this method and denaturing high pressure liquid chromatography (DHPLC). Eight of the total samples showed different results. Among them, two samples were diagnosed as having only SMN2 gene by DHPLC, however, they contained both SMN1 and SMN2 by our method. They were further confirmed by DNA sequencing. Our method showed good agreement with the DNA sequencing. The multiplex ligation-dependent probe amplification (MLPA) was used for confirming the other five samples, and showed the same results with our CE method. For only one sample, our CE showed different results with MLPA and DNA sequencing. One out of 284 samples (0.35%) belonged to mismatching. Our method provided a better accurate method and convenient method for clinical genotyping of SMA disease. [source] Simultaneous determination of low-molecular-weight organic acids and chlorinated acid herbicides in environmental water by a portable CE system with contactless conductivity detectionELECTROPHORESIS, Issue 10 2007Yan Xu Abstract This report describes a method to simultaneously determine 11 low-molecular-weight (LMW) organic acids and 16 chlorinated acid herbicides within a single run by a portable CE system with contactless conductivity detection (CCD) in a poly(vinyl alcohol) (PVA)-coated capillary. Under the optimized condition, the LODs of CE-CCD ranged from 0.056 to 0.270,ppm, which were better than for indirect UV (IUV) detection of the 11 LMW organic acids or UV detection of the 16 chlorinated acid herbicides. Combined with an on-line field-amplified sample stacking (FASS) procedure, sensitivity enhancement of 632- to 1078-fold was achieved, with satisfactory reproducibility (RSDs of migration times less than 2.2%, and RSDs of peak areas less than 5.1%). The FASS-CE-CCD method was successfully applied to determine the two groups of acidic pollutants in two kinds of environmental water samples. The portable CE-CCD system shows advantages such as simplicity, cost effectiveness, and miniaturization. Therefore, the method presented in this report has great potential for onsite analysis of various pollutants at the trace level. [source] Capillary electrophoresis of intact basic proteins using noncovalently triple-layer coated capillariesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 14 2009Rob Haselberg Abstract The usefulness of a noncovalent, positively charged capillary coating for the efficient analysis of intact basic proteins with CE was studied. Capillaries were coated by subsequent flushing with solutions of 10% w/v Polybrene (PB), 3% w/v dextran sulfate (DS), and again 10% w/v PB. Coating characterization studies showed that stable coatings could be produced which exhibited a pH-independent and highly reproducible EOF. The PB,DS,PB coating was evaluated with Tris phosphate BGEs of various pH using the four basic model proteins: ,-chymotrypsinogen A, ribonuclease A, cytochrome c, and lysozyme. Typical migration time RSDs for the proteins were less than 0.85%, and apparent plate numbers were above 125 000 using a capillary length of 40 cm. The high separation efficiency allowed detection of several minor impurities in the model proteins. Using a BGE of medium pH, the CE system with triple-layer coating appeared to be useful for the repeatable profiling of recombinant humanized mouse monoclonal immunoglobulin G1 showing a characteristic pattern of glycoforms. The CE system was also applied to the characterization of two llama antibodies, which were produced in Saccharomyces cerevisiae, revealing the presence of a side product in one of the antibodies. The high migration time stability allowed the reliable determination of antibody,antigen binding by monitoring migration time shifts. Finally, the feasibility of using the PB,DS,PB coated capillaries for CE with mass spectrometric detection was shown by the characterization of the impure llama antibody sample. [source] Quantitative capillary electrophoresis and its application in analysis of alkaloids in tea, coffee, coca cola, and theophylline tabletsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 2 2009Mengjia Li Abstract A quantitative CE (qCE) system with high precision has been developed, in which a 4-port nano-valve was isolated from the electric field and served as sample injector. The accurate amount of sample was introduced into the CE system with high reproducibility. Based on this system, consecutive injections and separations were performed without voltage interruption. Reproducibilities in terms of RSD lower than 0.8% for retention time and 1.7% for peak area were achieved. The effectiveness of the system was demonstrated by the quantitative analysis of caffeine, theobromine, and theophylline in real samples, such as tea leaf, roasted coffee, coca cola, and theophylline tablets. [source] Hydrophobicity-aided potentiometric detection of catecholamines, beta-agonists, and beta-blockers in a mixed-solvent capillary electrophoresis systemJOURNAL OF SEPARATION SCIENCE, JSS, Issue 1 2009Grzegorz Bazylak Abstract A series of cationic drug-like substances with distinct basicity, hydrogen-bonding ability, and hydrophobicity, including three catecholamines, two beta-agonists, and thirteen beta-blockers, was successfully detected in a capillary electrophoresis system using an end-capillary coupled potentiometric sensor consisting of a PVC-based liquid membrane deposited directly on a 100 ,m diameter copper rod. The electrophoretic separation was performed on a 72 cm×75 ,m id uncoated fused-silica capillary with an acidic background electrolyte containing phosphoric acid in a water,acetonitrile mixture, pH* 2.8. Samples were injected electrokinetically at 5.0 kV for 10 s and a running voltage of 19.5 kV was applied. Excluding the bufuralol/practolol pair, baseline separation of all substances was achieved in the developed CE system within 9 minutes. A linear relationship (R2 0.8752) between the sensitivity of the applied potentiometric detector and the parameter log P characterising the hydrophobicity of the analytes was demonstrated. The best observable limits of detection (LODs) were obtained for the highly hydrophobic substances, i. e. bufuralol (8.10×10,8 M injected concentration, S/N = 3), propranolol, alprenolol, and clenbuterol (ca. 1.10×10,7 M). In the case of hydrophilic catecholamines and carbuterol their LODs with potentiometric detection were lowered by a factor of almost one thousand, reaching a value of 6.6×10,5 M. [source] Inorganic analysis of biological fluids using capillary electrophoresisJOURNAL OF SEPARATION SCIENCE, JSS, Issue 11 2008Andrei R. Timerbaev Abstract This review article focuses on recent advances of CE in determination of inorganic species in biological fluids and covers the years of dedicated research in the field since 2001 when a previous similar review was published [1]. The most productive area, in which CE has distinctively progressed over the review period, encompasses assaying major inorganic anions and cations in blood serum and urine. Other applications include assessing less abundant analytes, e. g., heavy metals or seleno-compounds, and less abundant body fluids (saliva, sweat, etc.). Special emphasis is placed on developments in CE methodology that comprised modifications of separation and detection hardware and using specific electrolyte modifiers to enhance the resolution of a CE system. Significant progress in the application of in-line preconcentration methods in order to move CE ahead closer to trace analyte levels is also brought into focus. A series of tables detailing highly developed CE procedures and the analytical figures of merit accomplished are included. Finally discussed are further strategies for the method's expansion in the practice of biomedical and clinical laboratories where CE could likely acquire the status of a benchmark analytical technique. [source] Cover Picture: Electrophoresis 19'2010ELECTROPHORESIS, Issue 19 2010Article first published online: 29 SEP 2010 Issue no. 19 is a special issue on "CE and CEC Innovations" comprising 1 Fast Track manuscript and 20 manuscripts distributed over 5 separate parts. Part I has 5 research articles on novel trends in CEC. Part II has 4 research articles dealing with innovative methodologies. Part III reports a variety of interactive CE systems described in 5 research articles. Proteins and biomarkers are treated in 3 research articles making up part IV. The last 3 articles in this issue (Part V) are on detection approaches. The FAST TRACK article describes "An automated capillary electrophoresis system for high speed separation of DNA fragments based on a short capillary". [source] Cover Picture: Electrophoresis 22'2009ELECTROPHORESIS, Issue 22 2009Article first published online: 25 NOV 200 Issue no. 22 is a Special Issue on "CE and CEC Innovations" consisting of 24 important contributions in various areas of CE and CEC that are grouped into five different parts. Part I has 7 articles on novel "Stationary Phases for CEC". Part II is on "CE of Microorganisms and their Components and Interactions", and has 4 research articles. "Enantioseparations" constitute part III and has 3 research articles dealing with different chiral species and chiral CE systems. Part IV has 3 contributions on "Detection Approaches in CE". Part V is on "Capillary Coating, Affinity and Separation Media , Applications" and contains 7 research articles dealing with the separations of proteins, lipoproteins, bioactive inflammatory cytokines, inorganic and small organic anions, non-steroidal anti-inflammatory drugs, cell culture media and ancient DNA samples." [source] Comparative performances of selected chiral HPLC, SFC, and CE systems with a chemically diverse sample setCHIRALITY, Issue S1 2003Phil Borman Abstract Pharmaceutical companies have a continuous need to resolve new racemates. Analysis may be required in aqueous and nonaqueous media, or in the presence of several different sets of potentially interfering compounds. There is often a preparative requirement. For these reasons analysts may require a number of different separation systems capable of resolving a given pair of enantiomers. We wished to improve upon existing approaches that address this situation and undertook a program of work to screen over 100 racemates, selected for their chemical diversity, on over 100 different chiral HPLC, SFC, and CE systems. Here we report results of this comparison and illustrate the use of rapid gradient screening as a valuable tool for chiral method development. Chirality 15:S1,S12, 2003. © 2003 Wiley-Liss, Inc. [source] Copper-coated microsprayer interface for on-line sheathless capillary electrophoresis electrospray mass spectrometry of carbohydratesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 3 2006Alina D. Zamfir Abstract A sturdy home-built sheathless CE/ESI-QTOF-MS system was developed and optimized for carbohydrate analysis. The interface and employed methodology provided a simple analytical solution to laborious CE/MS interfacing methods and to problems in characterization of complex carbohydrate mixtures that require high-resolution separation of the components. The CE/ESI interface, feasible in any MS laboratory, consists of a one-piece CE column having the CE terminus in-laboratory shaped as a microsprayer and coated with copper. The CE microsprayer was inserted into an in-house made stainless steel clenching device and the whole assembly was mounted onto a quadrupole TOF mass spectrometer. The analytical potential of the interface in terms of suitability, microsprayer performance, copper coat durability, ionization efficiency, spray stability, and sensitivity was tested first on a simple mixture of standard saccharides, which were separated, resolved, and detected with high separation efficiency. The approach was next assessed for the screening of a biological sample, a complex mixture of O -glycosylated sialylated amino acids from urine of a patient suffering from Schindler disease. Preliminary data allow this method to be considered as one of general applicability in structural glycobiology and glycomics and easy to be implemented for proteomic surveys as well. [source] | ||||||||||