Online Isotachophoretic Sample Pretreatment in Ultratrace Determination of Paraquat and Diquat in Water by Capillary Zone Electrophoresis

Kaniansky, Dušan; Iványi, F.; Onuska, Francis I.

doi:10.1021/ac00083a007

Cited by 76 publications

(27 citation statements)

References 42 publications

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“…The higher the CB,s*, the smaller the right-hand side of condition (18) and the narrower the range of substances X fulfilling this condition. Note that, for CB,s* = 0, condition (18) showing the influence of &: to fulfill stacking condition (18) for a given X (iix,B), the CB,s*/CA,s* ratio must be lower than a certain value, given by condition (19). This condition has physical sense only if both l-iiB,B/iiX,B and…”

Section: Criteria Of Terminating-type Sample Self-stackingmentioning

confidence: 99%

Sample self‐stacking and sample stacking in zone electrophoresis with major sample components of like charge: General model and scheme of possible modes

1995

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A theoretical study is presented of zone electrophoretic behavior of samples that contain one or more minor analytes and at least one major ionogenic component of like charge. Based on a simple model comprising weak univalent anionic electrolytes, conditions are derived under which analytes are temporarily focused isotachophoretically into very narrow zones by a sample self-stacking effect provided by the major sample components. Requirements for minimal/maximal mobility and a background coion concentration dependent minimal concentration of a major sample component (stacker) are presented. For systems in which sample self-stacking does not apply, an expression for the concentrating factor is derived that involves the effects of both nonselective (classical) and selective sample stacking, the latter being a consequence of electrophoretic separation of the minor analyte from the major component. The theory derived is discussed with selected model examples by using both numerical calculation and computer simulation.

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Section: Criteria Of Terminating-type Sample Self-stackingmentioning

confidence: 99%

Sample self‐stacking and sample stacking in zone electrophoresis with major sample components of like charge: General model and scheme of possible modes

1995

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“…w x w Kaniansky et al 35 and Dombek and Stransky 36, x 37 studied the cleanup and separation of herbicides containing a quaternary ammonium cation such as Ž . paraquat, diquat and chlormequat Figure 6 .…”

Section: Separation Of Organic Cationsmentioning

confidence: 99%

Isotachophoresis: Trials, tribulations, and trends in trace analysis of organic and inorganic pollutants

et al. 1998

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The aim of this article is to summarize the present state of isotachophoresis (ITP) and its applications in organic and inorganic environmental trace analyses. The design and operation of an isotachophoretic instrumentation for the determination of pollutants is discussed. Application of the closed system to the analysis of drinking water, surface waters and industrial waste water is reviewed. The emphasis has been laid on the description of various application areas, most of them are illustrated by several characteristic practical examples of separation. Examples covering pollutants such as organic acids, phenols, nitrophenols, aldehydes, quaternary ammonium compounds, triazine herbicides, pyrethroid insecticides and separation of inorganic anions in mineral waters, surface and well waters and sewage are illustrated. The determination of inorganic cations in two different modes of operation such as anionic mode and in a cationic mode of operation is also covered. © 1998 John Wiley & Sons, Inc. J Micro Sep 10: 567–579, 1998

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“…Methods using gas chromatography-mass spectrometry (GC-MS) on selected QA drugs have been developed but intact QA compounds cannot be analyzed with GC-MS [9][10][11][12]. One approach is the hydrolysis of the isolated quaternary compound to cyclopentylmandelic acid which is then amenable to detection and confirmation following derivatization and analysis by GC-MS. A broad range of other chromatographic and spectrometric techniques have been reported for the analysis of QA drugs [13][14][15][16][17][18][19][20][21][22][23][24][25][26]. An inherent disadvantage of most of these analytical methods is the lack of specificity, resulting in identification and quantification issues in complex matrices, e.g., plasma [13].…”

Section: Introductionmentioning

confidence: 99%

“…Indeed, the cationic nature of the drugs does not lend itself well to liquid-liquid partition extraction methods [6,9,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Liquid-liquid extractions can only be an alternative when ion pairing is introduced.…”

Section: Introductionmentioning

confidence: 99%

Quantitative determination of glycopyrrolate in human plasma by liquid chromatography–electrospray ionization mass spectrometry: The use of a volatile ion-pairing agent during both liquid–liquid extraction and liquid chromatography

Storme

t’Kindt

Goeteyn

et al. 2008

Journal of Chromatography B

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a b s t r a c tThe work presented here deals with the development of a quantitative tool for the determination of the quaternary ammonium anticholinergic glycopyrrolate in human plasma samples. Mepenzolate was used as an internal standard. The plasma samples were subjected to a suitable sample clean-up consisting of a simple and relatively fast, two step liquid-liquid ion-pair extraction procedure. The chromatography, using the same volatile ion-pair reagent heptafluorobutyric acid (HFBA), takes only 10 min. Relative standard deviation of retention times was never above 2.26% (n = 36). The method was fully validated based on the US FDA Bioanalytical Method Validation Guidance for Industry. As such, a quantitative ESI-LC-MS(/MS) (TOF mass spectrometry) method was optimized for the absolute quantification of glycopyrrolate in human plasma in a concentration range from 0.101 to 101 ng/mL using a quadratic calibration function (R 2 = 0.9995), y = −2.21 × 10 −4 (±3.93 × 10 −5 ) × x 2 + 5.85 × 10 −2 (±5.27 × 10 −3 ) × x + 4.08 × 10 −3 (±4.82 × 10 −4 ). For the three QC concentrations (QC 1 0.252, QC 2 2.52, and QC 3 25.2 ng/mL) and the LLOQ (0.101 ng/mL), total precision was under 20% (18.0% (n = 6) at the LLOQ) and maximum accuracy was 112% (88.9% for the LLOQ, n = 6). Absolute matrix effect (maximum 133% ± 9.59, n = 3), absolute recovery (better than 41.8% ± 2.22, n = 3), relative (inter-subject) matrix effect (maximum 10.9% ± 1.45, n = 4) and process efficiency (better than 45.2% ± 5.74, n = 3) too were assessed at the 3 QC concentrations.

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Online Isotachophoretic Sample Pretreatment in Ultratrace Determination of Paraquat and Diquat in Water by Capillary Zone Electrophoresis

Cited by 76 publications

References 42 publications

Sample self‐stacking and sample stacking in zone electrophoresis with major sample components of like charge: General model and scheme of possible modes

Sample self‐stacking and sample stacking in zone electrophoresis with major sample components of like charge: General model and scheme of possible modes

Isotachophoresis: Trials, tribulations, and trends in trace analysis of organic and inorganic pollutants

Quantitative determination of glycopyrrolate in human plasma by liquid chromatography–electrospray ionization mass spectrometry: The use of a volatile ion-pairing agent during both liquid–liquid extraction and liquid chromatography

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