Ion pair partition chromatography of organic ammonium compounds

Eksborg, Staffan; Schill, G

doi:10.1021/ac60334a019

Cited by 130 publications

(22 citation statements)

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“…Ion-pair chromatography, first developed by Schill and coworkers [1,2], is a useful separation technique for organic molecules having cationic, anionic, and zwitterionic characteristics [3][4][5]. Appropriate ion-pair reagents used with reversed-phase stationary columns in LC have been utilized for the separation of amino organic compounds [6][7][8]).…”

Section: Introductionmentioning

confidence: 99%

Isolation of underivatized amino acids by ion-pair high performance liquid chromatography for precise measurement of nitrogen isotopic composition of amino acids: Development of comprehensive LC × GC/C/IRMS method

Takano

Chikaraishi

Ohkouchi

2015

International Journal of Mass Spectrometry

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a b s t r a c tNitrogen isotopic composition of amino acids has been widely applied to biochemical, ecological, archeological, and biogeochemical studies in an attempt to trace nitrogen source and transformation processes. For accurate isotope analysis of individual amino acids, we validated a preparative method involving the isolation of underivatized amino acids by ion-pair chromatographic separation and confirmed the consistency of nitrogen isotope composition. Ion-pair reversed-phase liquid chromatography coupled with electrospray ionization mass spectrometry (LC/ESI-MS) and gas chromatography/combustion coupled with isotope ratio mass spectrometry (GC/C/IRMS) were conducted for the purpose of separation of underivatized amino acids and nitrogen isotopic analysis, respectively. Firstly, we confirmed the resolution of proteinogenic and non-proteinogenic amino acids by the preparative ion-pair LC separation. Diagnostic product ions determined by mass spectrometry can support the rapid identification of individual amino acids in screening analyses. Secondly, we observed no dependency on nitrogen isotopic composition for the injection amount of underivatized amino acids and even for different chemical formula including neutral, acidic, sulfur-containing, heterocyclic, and aromatic species. The recovery during the LC was 91.7 ± 4.3% (n = 3). The present method and strategy of LC coupled with GC/C/IRMS (i.e., comprehensive LC × GC/C/IRMS) are useful for the high precision determination of the nitrogen isotopic composition of amino acids, in conjunction with an appropriate pre-treatment of cation-exchange chromatographic procedures.

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Section: Introductionmentioning

confidence: 99%

Isolation of underivatized amino acids by ion-pair high performance liquid chromatography for precise measurement of nitrogen isotopic composition of amino acids: Development of comprehensive LC × GC/C/IRMS method

Takano

Chikaraishi

Ohkouchi

2015

International Journal of Mass Spectrometry

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“…Indeed, inspection and detailed analysis of the data fitting of our plots indicates curvature. Nonetheless, it is very well known that the extraction of hydrophobic cations from water into low polarity solvents such as c-hexane and methylene chloride is greatly enhanced by changing the anion from chloride to perchlorate and other more hydrophobic anions [31,32].…”

Section: Effect Of Anionic Additives On Cationic Drugs On Sb-c18 In 0mentioning

confidence: 99%

An unexpected observation concerning the effect of anionic additives on the retention behavior of basic drugs and peptides in reversed-phase liquid chromatography

Wang

Carr

2007

Journal of Chromatography A

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Anionic species with ion pair forming ability are commonly used to enhance the retention and efficiency of basic analytes in RPLC separations. However, little is known about the interactions between organic mobile phase modifiers and such ion pairing anions. In this work, we measured the magnitude of the retention increase of basic drugs and peptides upon addition of strong inorganic ion pairing anions (e.g. perchlorate) as a function of the volume fraction of modifier in acidic water-acetonitrile mobile phases on two different stationary phases. We found that the increase in retention upon addition of various salts depended strongly on the eluent strength. In general, larger retention increases upon addition of the anion were observed at higher organic fractions. Regression of retention against the volume fraction of organic modifier indicated that the ion pair forming anions substantially decreased S values while only slightly changing ln k' w values. The decrease in S is the major cause of the retention increase of basic drugs and peptides when such anions are added to the mobile phase.

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“…Much of the theory and application of ion-pair techniques has been attributed to Schill and coworkers in Sweden (1)(2)(3)(4). One distinct advantage of using ion-pairing in pharmaceutical analysis is that the low detection response of some drugs can be Salicylic Acid greatly improved using counter-ions of high molar absorptivity or fluorescence intensity (5)(6)(7)(8).…”

Section: Introductionmentioning

confidence: 99%

Flow Injection Analysis of Carboxylic Acid Drugs Using Cationic Dyes and On-Line Ion-Pair Extraction

Stewart¹,

Lang²,

Honigberg³

1988

Journal of Liquid Chromatography

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Journal of Liquid ChromatographyPublication details, including instructions for authors and subscription information:ABSTRACT A flow injection system containing an on-line ion-pair extractor has been designed for the analysis of carboxylic acid drugs using either spectrophotometric detection with gentian violet as counterion or fluorescence detection with acridine orange. Salicylic acid, valproic acid, and ibuprofen were selected as model drugs. phosphate buffer-absolute methanol was pumped through the system at 1 ml/min. A chloroform solution of the cationic dye was pumped into the mobile phase at 1.25 ml/min and the chloroform layer containing the dye-drug ion-pair separated prior to detection. Peak height and absorbance were linear €or salicylic acid, valproic acid, and ibuprofen in the 0.5-10, 5-50, and 1-10 pg/ml ranges, respectively. Peak height and fluorescence were linear for salicylic acid, valproic acid, and ibuprofen in the 0.13-5, 2.5-50, and 0.5-20 ug/ml ranges, respectively. Accuracy and precision for the spectrophotometric assays were in the 2-6% and 3.3-6.6% ranges, respectively, and in the 0.3-4% and 1.3-5.4% ranges, respectively, for the fluorescence assays. Peak height and absorbance were also shown to be linear in the A mobile phase of 9O:lO aqueous pH 7 3353 Copyright 0 1988 by Marcel Dekker, Inc. Downloaded by [University of Calgary] at 02:40 06 February 2015 3354 STEWART, LANG, AND HONIGBERG16-500 pg/ml range for prostaglandin PGF precision of 1-3% and 5 4 % . respectively?afor spiked samples.Commercial dosage forms containing valproic acid and ibuprofen were assayed by the spectrophotometric assay and found to be within acceptable USP limits. Spiked ibuprofen samples at the 5 and 10 pg/ml level were assayed using an octadecylsilane column inserted into the flow injection system. One to two percent accuracy and 2.5-5% precision were obtained for the drug using the FIA-column system. with accuracy and

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Ion pair partition chromatography of organic ammonium compounds

Cited by 130 publications

References 8 publications

Isolation of underivatized amino acids by ion-pair high performance liquid chromatography for precise measurement of nitrogen isotopic composition of amino acids: Development of comprehensive LC × GC/C/IRMS method

Isolation of underivatized amino acids by ion-pair high performance liquid chromatography for precise measurement of nitrogen isotopic composition of amino acids: Development of comprehensive LC × GC/C/IRMS method

An unexpected observation concerning the effect of anionic additives on the retention behavior of basic drugs and peptides in reversed-phase liquid chromatography

Flow Injection Analysis of Carboxylic Acid Drugs Using Cationic Dyes and On-Line Ion-Pair Extraction

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