New leading electrolyte for the direct determination of chloride and other anions in analytical isotachophoresis

The utility of three various analytical techniques [ion chromatography (IC), capillary electrophoresis (CE) and isotachophoresis (ITP)] was tested in the determination of counter-ions in synthetic peptides. The analyzed ions were acetates, trifluoroacetates and chlorides. IC provided the best results; CE, except limit of detection and limit of quantification, exhibited the comparable results. ITP was classified as the less useful because of the problem with the determination of the chloride ions. Nevertheless, all the three techniques were able to analyze trifluoroacetates and acetates ions with satisfactory results. Except analytical methods, three procedures using hydrochloric acid (HCl) (at two different concentrations) and acetic acid as sample solvents processed by lyophilization were tested. It has been found that the lyophilization not only by HCl but also by acetic acid is a simple and cheap procedure for removal of toxic trifluoroacetic counter-ions from peptides on satisfactory levels.

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“…For this reason, the anion was not analyzed in the tested peptide. However, there were attempts to determine chloride ions using different LEs .…”

Section: Resultsmentioning

confidence: 99%

Determination of counter‐ions in synthetic peptides by ion chromatography, capillary isotachophoresis and capillary electrophoresis

Mrozik

Markowska

Guzik

et al. 2012

Journal of Peptide Science

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“…However, neither their structures nor their gas‐phase acidities are known. The acidity of aqueous dithionic acid H 2 S 2 O 6 has recently been determined as p K a = 1.9,16 but no data for the other acids are available. The structures of the monoanions HS n O 6 − are also unknown since no corresponding salts have ever been isolated.…”

Section: Introductionmentioning

confidence: 99%

Gas-Phase Structures and Acidities of the Sulfur Oxoacids H2SnO6 (n = 2−4) and H2S2O7

Otto¹,

Steudel²

2001

Eur. J. Inorg. Chem.

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The gas‐phase geometries, dipole moments, enthalpies, and Gibbs free energies of dithionic acid H2S2O6, trithionic acid H2S3O6, tetrathionic acid H2S4O6, and disulfuric acid H2S2O7 have been determined by ab initio MO calculations at various levels of theory. The most stable conformations of H2S2O6 and H2S2O7 are of C2 symmetry, the other two acids are of C1 symmetry. The gas‐phase acidities defined as ΔG°298 of the deprotonation reaction obtained at the {MP2/6‐311++ G(3df, 3pd)//MP2/6‐31+ G(d) + ZPVE[HF/6‐31+ G(d)]} level are as follows [kJ·mol−1]: H2S2O6 1180, H2S3O6 1162, H2S4O6 1156, H2S2O7 1171. All four acids are much stronger than fluorosulfuric acid and chlorosulfuric acid in the gas phase. The decomposition of H2S2O7 into SO3 and H2SO4 is slightly endothermic and the same holds for the decomposition of H2S3O6 into SO3 and H2S2O3, but the reaction of H2S2O6 to SO2 and H2SO4 is strongly exothermic. The structures of the monoanions HS2O6−, HS3O6−, HS4O6−, and HS2O7− are characterized by intramolecular hydrogen bonds.

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“…Methodological research has brought some new electrolyte components. Dithionate was suggested as a new LE for direct determination of chloride and other anions above pH 3 [43]. Polyethylene glycol was investigated as a complexing agent in acidic nonbuffered systems for the separation of mixtures of metal cations and a new approach for the estimation of polymer-metal stability constants from ITP data was proposed [44].…”

Section: Theory and Methodologymentioning

confidence: 99%

Recent progress in capillary isotachophoresis

Gebauer

Boček

2000

Electrophoresis

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New leading electrolyte for the direct determination of chloride and other anions in analytical isotachophoresis

Cited by 23 publications

References 7 publications

Determination of counter‐ions in synthetic peptides by ion chromatography, capillary isotachophoresis and capillary electrophoresis

Determination of counter‐ions in synthetic peptides by ion chromatography, capillary isotachophoresis and capillary electrophoresis

Gas-Phase Structures and Acidities of the Sulfur Oxoacids H2SnO6 (n = 2−4) and H2S2O7

Recent progress in capillary isotachophoresis

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