Transient pseudo-isotachophoretic stacking in analysis of plasma for homocysteine by capillary zone electrophoresis

Kubalczyk, Paweł; Bald, Edward

doi:10.1007/s00216-005-0271-7

Cited by 33 publications

(24 citation statements)

References 36 publications

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“…The analytical criteria (precision, accuracy) are comparable with those obtained by analogous methods. [12][13][14]21,22 We conclude that this method may find application in the routine analysis of blood plasma samples in experimental and clinical laboratories. Further improvement of the deproteinization approaches based on ultracentrifugation or solid-phase extraction may facilitate sample preparation and speed up the process.…”

Section: Discussionmentioning

confidence: 80%

“…A few rather sensitive HPLC approaches (LOD < 1 μM) were also proposed in which the application of reagents, such as 2-chloro-1-methylquinoline tetrafluoroborate (CMQT), 8 1,1′-thiocarbonyldiimidazole (TCDI), 9 4,4′-dithiodipyridine 10 and 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB) 11 made it possible to use conventional UV-detectors. Later approaches based on CE-UV with the use of CMQT 12,13 and TCDI 14 were proposed. Although these approaches had a lower sensitivity, they had a number of advantages compared to HPLC such as high performance, selectivity (specificity) and affordability.…”

Section: Introductionmentioning

confidence: 99%

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Determination of Blood Plasma Aminothiols Using Derivatization-enhanced Capillary Transient Isotachophoresis

et al. 2018

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Experimental Reagents and chemicalsAcetonitrile (ACN; 99.9%; Lab-Scan, Gliwice, Poland); CHCl3 (>99.8% for LC; Merck, Darmstadt, Germany); L-Cys 97%, dimethyl sulfoxide (DMSO, >99.8%), dithiothreitol (DTT, >99%), DTNB, formic acid 98%, D,L-Hcy >95%, GSH reduced >98%, N-(2-mercaptopropionyl)glycine (MPG), NaCl 99.5%, A sensitive capillary electrophoresis method was developed for the determination of aminothiol (cysteine, homocysteine, and glutathione) total levels in human blood plasma. Analytes were derivatized with Ellman's reagent (5,5′-dithiobis(2-nitrobenzoic acid)) after reduction with dithiothreitol. Liquid-liquid extraction was applied to purify the samples and concentrate the analytes. Total analysis time was 7.5 min using a silica capillary (50 μm i.d.; effective separation length 23.5 cm). Electrophoretic separation was performed using 50 mM citric acid with 20 mM triethanolamine (pH 3) containing 2% Ficoll 400. Detection limit was 0.8 μM for glutathione and 0.3 μM for both cysteine and homocysteine. Accuracy was 94 -107%, repeatability and reproducibility were ca. 2.7 -3.5 and 2.5 -6.5%, respectively.

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Section: Discussionmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Determination of Blood Plasma Aminothiols Using Derivatization-enhanced Capillary Transient Isotachophoresis

et al. 2018

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“…The authors reported a 10 000-130 000-fold improvement in the limits of detection, which makes it feasible to analyze low-picomolar concentrations of DNA, amino acids, and proteins within 2-8 min. A third paper described used pseudotransient isotachophoretic to increase sensitivity of homocysteine detection in plasma samples using commercial CE systems and UV detection (38). Here, acetonitrile was added to the sample containing high concentration of salts (e.g., plasma).…”

Section: Processes Prior To Cementioning

confidence: 99%

Capillary Electrophoresis in Bioanalysis

2008

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Science reports ∼4800 hits on capillary electrophoresis (CE) including 410 reviews. Because of the prominence of CE techniques in bioanalysis, we decided make them the focus of this review and selected 200 hundred papers representing advances in this field. The selected papers cover advances in CE theory, instrumentation, and methodologies that are specific to various analytes of biological origin or relevance. The group of analytes includes nucleic acids, proteins and peptides, carbohydrates, lipids, single cells, and bioparticles. In addition, we have included advances in the use of CE to define functional assays or to investigate biomolecular interactions. The use of microfabricated devices for CE analysis was not included because this is already covered in other review. Technique Developments Separation SchemesDetermining the velocity of the electroosmotic flow (EOF) and how it changes during an electrophoretic separation is still an important research topic. A simple method for EOF measurements using so-called thermal marks was reported (1). Here, a tungsten filament caused punctual heating at the capillary wall and caused a perturbation in the electrolyte concentration. A sequence of these "thermal marks" then migrated with the EOF until each mark reached and was detected by a conductivity detector. The feasibility of using thermal marks as internal EOF standards in different separation systems was thereby demonstrated.Isoelectric focusing separates amphoteric analytes such as proteins or peptides by the differences in their isoelectric points. Most of the reports on capillary isoelectric focusing (cIEF) describe an initial focusing phase after which the focused zones are mobilized and detected. A dynamic cIEF method for protein analysis was reported (2). This technique made it possible to control each protein's position and focused width by moving the pH gradient within the capillary through manipulation of the electric fields. An important advantage of this approach is the capability of collecting focused analytes from the central section, suggesting that there may be great potential for introducing selectively focused proteins to a second separation dimension such as LC or CE.Micellar electrokinetic capillary chromatography (MEKC) is typically incompatible with electrospray mass spectrometry (ESI-MS) because the nonvolatile surfactants in the micellar phase result in complicated adduct formation and loss of sensitivity during the electrospray process and because the presence of the organic solvent needed for electrospray may cause instability in the micellar phase. These drawbacks were overcome by using synthetic polymeric surfactants that can work as a pseudostationary phase and provide stable electrospray (3). The polymeric surfactant was made by polymerizing three amino acidderived (L-leucinol, L-isoleucinol, L-valinol) sulfated chiral surfactants. These polymeric

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“…Based on 3δ blank /k (where δ blank is the standard deviation of the blank solution and k is the slope of the calibration plot), the limit of detection (LOD) was attained of 12.5 nM. A comparison of the analytical performances with that previously reported methods [4][5][6]8,11,13,15,[30][31][32][33][34][35] for the determination of L-Cys is summarized in Table 2. As can be seen from the table, the present method is an ideal candidate for L-Cys analysis.…”

Section: Fluorescent Detection Of L-cys Via Rb1mentioning

confidence: 99%

“…Therefore, identifying and quantifying L-Cys is very important and considerable efforts have been made to develop high efficient methods for its determination [4][5][6]. Common separation techniques such as high performance liquid chromatography (HPLC), capillary electrophoresis (CE) and gas chromatography (GC), coupled with fluorescence or electrochemical detection, are usually utilized for assaying L-Cys, but they are often inconvenient to operate and often require time consuming sample preparation and separation procedures [7,8]. Because L-Cys possesses a very low molar absorptivity and lacks a suitable chromophore, derivatization with fluorescent reagents is typically used for detection [9].…”

Section: Introductionmentioning

confidence: 99%

Chemodosimeter-based fluorescent detection of l-cysteine after extracted by molecularly imprinted polymers

Cai

Zhong

et al. 2014

Talanta

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Chemodosimeter Rhodamine B a b s t r a c tA chemodosimeter-based fluorescent detection method coupled with molecularly imprinted polymers (MIPs) extraction was developed for determination of L-cysteine (L-Cys) by combining molecular imprinting technique with fluorescent chemodosimeter. The MIPs prepared by precipitation polymerization with L-Cys as template, possessed high specific surface area of 145 m 2 /g and good thermal stability without decomposition lower than 300 1C, and were successfully applied as an adsorbent with excellent selectivity for L-Cys over other amino acids, and enantioselectivity was also demonstrated. A novel chemodosimeter, rhodamine B1, was synthesized for discriminating L-Cys from its structurally similar homocysteine and glutathione as well as various possibly co-existing biospecies in aqueous solutions with notable fluorescence enhancement when adding L-Cys. As L-Cys was added with increasing concentrations, an emission band peaked at 580 nm occurred and significantly increased in fluorescence intensity, by which the L-Cys could be sensed optically. High detectability up to 12.5 nM was obtained. An excellent linearity was found within the wide range of 0.05-50 μM (r¼ 0.9996), and reasonable relative standard deviations ranging from 0.3% to 3.5% were attained. Such typical features as high selectivity, high sensitivity, easy operation and low cost enabled this MIPs-fluorometry to be potentially applicable for routine detection of trace L-Cys.

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Transient pseudo-isotachophoretic stacking in analysis of plasma for homocysteine by capillary zone electrophoresis

Cited by 33 publications

References 36 publications

Determination of Blood Plasma Aminothiols Using Derivatization-enhanced Capillary Transient Isotachophoresis

Determination of Blood Plasma Aminothiols Using Derivatization-enhanced Capillary Transient Isotachophoresis

Capillary Electrophoresis in Bioanalysis

Chemodosimeter-based fluorescent detection of l-cysteine after extracted by molecularly imprinted polymers

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