On-column chelation of metal ions in capillary zone electrophoresis

Haumann, I.; Bächmann, K.

doi:10.1016/0021-9673(95)00469-9

Cited by 43 publications

(31 citation statements)

References 30 publications

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“…Based on the reported references, 4,8,10,39,40 some CE systems with different terms of the separation mode and back ground electrolyte (BGE) composition were compared for the separation of metal-EDTA complexes: i) 7.5 mM salicylic acid + 0.1 mM EDTA + 0.02 mM hexadecyltrimethylammonium bromide (HTAB), pH 4.01;…”

Section: Separation Mode and Back Ground Electrolytementioning

confidence: 99%

“…4 ii) 10 mM sodium acetate (pH 4.8) + 2 mM tartaric acid + 2.0 mM tetradecyltrimethylammonium bromide (TTAB); 8 iii) 40 mM NaH2PO4-Na2B4O7 buffer, pH 7.0 + 5.0 mM EDTA + 10 mM sodium dodecylsulfate (SDS); 10 iv) 95 mM phosphate (pH 7.1) + 0.5 mM TTAB; 39 v) 10 mM sodium acetate (or phosphate) + 5 mM hydroxyisobutyric acid (HIBA) + 0.1 mM cetyltrimethylammonium bromide (CTAB); and vi) 0.5% acetic acid and 10 mM imidazole in methanol. 40 Unfortunately, even though these CE running electrolytes were well used in the reported references, they provided bad separation for free EDTA, Pb-EDTA and Cu-EDTA.…”

Section: Separation Mode and Back Ground Electrolytementioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

“…[4][5][6][7] Ethylenediaminetetraacetic acid (EDTA) has also been used for this purpose. [8][9][10][11] EDTA is known to complex with metal ions in a 1:1 ratio, and the chelates are always negalively charged whatever the charge on the cations. 4,12 As a principally electrophoretic property, metal-EDTA anionic complexes could be successfully separated due to inherent differences in the electrophoretic mobilities.…”

Section: Introductionmentioning

confidence: 99%

“…Until now, on-column derivatization, also called in-capillary derivatization, has been applied to determine various types of analyte by one of three different strategies: zone-passing, at-inlet and throughout capillary derivatization. 2,8,[13][14][15] These studies have proven that the sensitivity could be sharply increased by using in-capillary derivatization.For the latter problem, the weak UV-absorption of most metal ions, several preconcentration methods have been developed to overcome the sensitivity problem, such as isotachophoresis, 16 [28][29][30] In addition, the sensitivity for the metal determination could be improved by using on-line preconcentration in micellar electrokinetic chromatography 45 and CE-laser induced fluorescence. 46 Increasing the optical path length by incorporating a bubble cell 31,32 or a U-shaped cell 33,34 is one of the means to improve the sensitivity of a UV detector.…”

mentioning

confidence: 96%

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Determination of Pb(II), Cu(II) and Fe(III) with Capillary Electrophoresis Using Ethylenediaminetetraacetic Acid as a Complexing Agent and Vancomycin as a Complex Selector

2006

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IntroductionIn the past decades, capillary electropheresis (CE) has been considered to be a powerful method, and widely applied to analyze many of different substances, ranging from small inorganic ions to large bio-macromolecules, due to many advantages, such as high separation speed and efficiency, very low running costs and low sample volume injected (e.g., 2 -10 nl). Metal-ion analysis, 1-3 however, covers a relatively small part of CE applications compared with separations in the areas of pharmaceuticals, oligonucleotides, proteins and peptides. Considering metal-ion analysis, problems occur due to (i) the similar electrophoretic mobilities and (ii) the weak UV absorption of most metal ions.The former problem is because most transition metal ions have similar mobilities due to their similar size and identical charge. 4 To achieve an electrophoretic separation, the mobilities have to be modified by introducing a complex forming equilibrium. If different degrees of complexation result for the ions during the interaction with a ligand, their apparent electrophoretic mobilities should also be different. Various reports can be found in the literature describing organic acids as complexing agents for improving the resolution in CE separation. These include oxalic acid, lactic acid, tartaric acid and hydroxyisobutyric acid. [4][5][6][7] Ethylenediaminetetraacetic acid (EDTA) has also been used for this purpose. [8][9][10][11] EDTA is known to complex with metal ions in a 1:1 ratio, and the chelates are always negalively charged whatever the charge on the cations. 4,12 As a principally electrophoretic property, metal-EDTA anionic complexes could be successfully separated due to inherent differences in the electrophoretic mobilities. However, in practice, it also suffers from poor selectivities, and is not sensitive. Until now, on-column derivatization, also called in-capillary derivatization, has been applied to determine various types of analyte by one of three different strategies: zone-passing, at-inlet and throughout capillary derivatization. 2,8,[13][14][15] These studies have proven that the sensitivity could be sharply increased by using in-capillary derivatization.For the latter problem, the weak UV-absorption of most metal ions, several preconcentration methods have been developed to overcome the sensitivity problem, such as isotachophoresis, 16 [28][29][30] In addition, the sensitivity for the metal determination could be improved by using on-line preconcentration in micellar electrokinetic chromatography 45 and CE-laser induced fluorescence. 46 Increasing the optical path length by incorporating a bubble cell 31,32 or a U-shaped cell 33,34 is one of the means to improve the sensitivity of a UV detector. U-shaped cells, usually a bent capillary, with a few millimeters of the capillary parallel to the optical path, can provide a higher sensitivity, but a loss of resolution prevents this method from further development. 35 Vancomycin is a macrocyclic antibiotic containing in its structure 18 asymmetric cent...

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Section: Separation Mode and Back Ground Electrolytementioning

confidence: 99%

Section: Separation Mode and Back Ground Electrolytementioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 96%

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Determination of Pb(II), Cu(II) and Fe(III) with Capillary Electrophoresis Using Ethylenediaminetetraacetic Acid as a Complexing Agent and Vancomycin as a Complex Selector

2006

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Determination of metal cations in microchip electrophoresis using on-chip complexation and sample stacking

et al. 1998

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Capillary Electrophoresis for the Simultaneous Determination of Metals by Using Ethylenediamine Tetraacetic Acid as Complexing Agent and Vancomycin as Complex Selector

2006

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A new separation system of capillary electrophoresis for the simultaneous determination of metals by using ethylenediamine tetraacetic acid (EDTA) as complexing agent and employing vancomycin as complex selector was described. The Z-shape cell capillary electrophoresis was used to enhance the sensitivity for the determination of the complexes of Cu(II), Ni(II), Co(II) and Fe(III) with EDTA. The partial filling method (co-current mode) was used in order to increase the selectivity of the electrophoretic method, meanwhile vancomycin was not present at the detector path during the detection of metal-EDTA complexes. The vancomycin concentration, phosphate concentration and pH of the buffer strongly influenced mobility, resolution and selectivity of the studied analytes. Under the optimal condition, the relative standard deviations (n＝5) of the migration time and the peak area were less than 3.14% and 7.35%, respectively. Application of the Z-shape cell capillary electrophoresis method with UV detection and vancomycin loading led to the reliable determination of these metal ions in tap water and the recoveries were 97%-101%. The detection limits based on a signal to noise ratio of 3∶1 were found in the range of 2-10 µg•L -1.

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On-column chelation of metal ions in capillary zone electrophoresis

Cited by 43 publications

References 30 publications

Determination of Pb(II), Cu(II) and Fe(III) with Capillary Electrophoresis Using Ethylenediaminetetraacetic Acid as a Complexing Agent and Vancomycin as a Complex Selector

Determination of Pb(II), Cu(II) and Fe(III) with Capillary Electrophoresis Using Ethylenediaminetetraacetic Acid as a Complexing Agent and Vancomycin as a Complex Selector

Determination of metal cations in microchip electrophoresis using on-chip complexation and sample stacking

Capillary Electrophoresis for the Simultaneous Determination of Metals by Using Ethylenediamine Tetraacetic Acid as Complexing Agent and Vancomycin as Complex Selector

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