Measurement of adenosine by capillary zone electrophoresis with on-column isotachophoretic preconcentration

Wang, Chao-Cheng; McCann, William P.; Beale, Stephen C.

doi:10.1016/0378-4347(95)00416-5

Cited by 30 publications

(8 citation statements)

References 49 publications

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“…Although useful, as indicated elsewhere in the review, CE can lack sensitivity due to the small sample volume injected. However, by using stacking methods developed for CZE [128,129] or MEKC [130], concentration of anions, cations, and electrically neutral analytes can be used to overcome this lack of sensitivity.…”

Section: Pharmacokinetic Studiesmentioning

confidence: 99%

Capillary electrophoresis and the clinical laboratory

et al. 2006

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Over the past 15 years, CE as an analytical tool has shown great promise in replacing many conventional clinical laboratory methods, such as electrophoresis and HPLC. CE's appeal was that it was fast, used very small amounts of sample and reagents, was extremely versatile, and was able to separate large and small analytes, whether neutral or charged. Because of this versatility, numerous methods have been developed for analytes that are of clinical interest. Other than molecular diagnostic and forensic laboratories CE has not been able to make a major impact in the United States. In contrast, in Europe and Japan an increasing number of clinical laboratories are using CE. Now that automated multicapillary instruments are commercially available along with cost-effective test kits, CE may yet be accepted as an instrument that will be routinely used in the clinical laboratories. This review will focus on areas where CE has the potential to have the greatest impact on the clinical laboratory. These include analyses of proteins found in serum and urine, hemoglobin (A1c and variants), carbohydrate-deficient transferrin, forensic and therapeutic drug screening, and molecular diagnostics.

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Section: Pharmacokinetic Studiesmentioning

confidence: 99%

Capillary electrophoresis and the clinical laboratory

et al. 2006

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“…The former combines a microchemical adsorption preconcentration technique, such as the solidphase extraction to CE. The latter includes various stacking methods [10][11][12][13][14][15][16][17][18][19][20][21][22][23] based on the conductivity difference between sample and running buffer. Isotachophoresis is another electrophoretic concentration method [24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Isoelectric focusing sample injection for capillary electrophoresis of proteins

Wu¹,

Zhang²,

Onoda³

2005

Electrophoresis

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Carrier ampholyte-free isoelectric focusing (IEF) sample injection (concentration) for capillary electrophoresis (CE) is realized in a single capillary. A short section of porous capillary wall was made near the injection end of a capillary by HF etching. In the etching process, an electric voltage was applied across the etching capillary wall and electric current was monitored. When an electric current through the etching capillary was observed, the capillary wall became porous. The etched part was fixed in a vial, where NaOH solution with a certain concentration was added during the sample injection. The whole capillary was filled with pH 3.0 running buffer. The inlet end vial was filled with protein sample dissolved in the running buffer. An electric voltage was applied across the inlet end vial and etched porous wall. A neutralization reaction occurs at the boundary (interface) of the fronts of H+ and OH-. A pH step or sharp pH gradient exists across the boundary. When positive protein ions electromigrate to the boundary from the sample vial, they are isoelectricelly focused at points corresponding to their pH. After a certain period of concentration, a high voltage is applied across the whole capillary and a conventional CE is followed. An over 100-fold concentration factor has been easily obtained for three model proteins (bovine serum albumin, lysozyme, ribonuclease A). Furthermore, the IEF sample concentration and its dynamics have been visually observed with the whole-column imaging technique. Its merits and remaining problem have been discussed, too.

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“…These examples demonstrate the interest in the development of new analytical methods for the quantitative determination of such components. The most extensively used techniques are HPLC and capillary electrophoresis, which permit the analysis of both majority and minority bases. −,− However, these analyses are quite time-consuming and other simpler methods are preferred for the determination of majority bases, as in the case of pharmaceutical products. Among these simpler methods, potentiometric acid−base titrations have been proposed for the quantitative analysis of mixtures of compounds that present acid−base properties, such as the nucleic acid components.…”

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confidence: 99%

Procedure for the Quantitative Determination of Mixtures of Nucleic Acid Components Based on Multivariate Spectrophotometric Acid−Base Titrations

et al. 1998

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A new procedure for the quantitative determination of mixtures of nucleic acid components, based on continuous spectrophotometric acid-base titrations and multivariate curve resolution, is proposed. The procedure simultaneously takes into account the spectroscopic and acid-base properties of the compounds, which leads to a higher selectivity. Furthermore, quantitative determination of an analyte in a complex mixture is performed using a synthetic solution as standard containing only the analyte of interest. An intrinsic difficulty in the analysis of spectrometric titration data is the presence of rank deficiency due to closure for the mixtures of two or more compounds. An additional problem can be encountered in some mixtures if species spectra or species concentration profiles are practically identical (rank overlap). However, even in the presence of these rank difficulties, accurate quantitation with prediction errors lower than 5% was obtained. The presence of unknown and uncalibrated interferences in the samples does not affect the quantitative determination of the analyte of interest. The proposed procedure was successfully applied to the analysis of real samples (pharmaceuticals) using synthetic external standards.

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Measurement of adenosine by capillary zone electrophoresis with on-column isotachophoretic preconcentration

Cited by 30 publications

References 49 publications

Capillary electrophoresis and the clinical laboratory

Capillary electrophoresis and the clinical laboratory

Isoelectric focusing sample injection for capillary electrophoresis of proteins

Procedure for the Quantitative Determination of Mixtures of Nucleic Acid Components Based on Multivariate Spectrophotometric Acid−Base Titrations

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