Separating stereoisomers of di‐, tri‐, and tetrapeptides using capillary electrophoresis with contactless conductivity detection

Gong, Xiao Yang; Dobrunz, Dorninik; Kümin, Michael; Wiesner, Markus; Revell, Jefferson D.; Wennemers, Helma; Hauser, Peter C.

doi:10.1002/jssc.200700461

Cited by 29 publications

(23 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Significant applications include separation of short peptides [6][7][8][9][10][11][12], organic anions [13,14], proteins, and protein ''charge ladders'' [15][16][17], stereoisomers [18], and also the study of complex formation [12,[19][20][21]. There are a number of factors that influence the effectiveness of separating species in a particular system and these include the solvent, composition of BGE, temperature, pH, sample concentration, nature of the capillary (its diameter, whether it is ''coated'', etc.…”

Section: Introductionmentioning

confidence: 99%

The dependence of the electrophoretic mobility of small organic ions on ionic strength and complex formation

et al. 2010

View full text Add to dashboard Cite

The ionic strength dependence of the electrophoretic mobility of small organic anions with valencies up to -3 is investigated in this study. Provided the anions are not too aspherical, it is argued that shape and charge distribution have little influence on mobility. To a good approximation, the electrophoretic mobility of a small particle should be equal to that of a model sphere with the same hydrodynamic radius and same net charge. For small ions, the relaxation effect (distortion of the ion atmosphere from equilibrium due to external electric and flow fields) is significant even for monovalent ions. Alternative procedures of accounting for the relaxation effect are examined. In order to account for the ionic strength dependence of a specific set of nonaromatic and aromatic anions in aqueous solution, it is necessary to include complex formation between the anion with species in the BGE. A number of possible complexes are considered. When the BGE is Tris-acetate, the most important of these involves the complex formed between anion and Tris, the principle cation in the BGE. When the BGE is sodium borate, an anion-anion (borate) complex appears to be important, at least when the organic anion is monovalent. An algorithm is developed to analyze the ionic strength dependence of the electrophoretic mobility. This algorithm is applied to two sets of organic anions from two independent research groups.

show abstract

Section: Introductionmentioning

confidence: 99%

The dependence of the electrophoretic mobility of small organic ions on ionic strength and complex formation

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Later on they applied these selectors to separate the enantiomers of the peptide Ala-Gly and the four stereoisomers of Ala-Leu-Gly using MCE [32]. Although the migration times were significantly longer in this case they could clearly resolve a 0.5% impurity of L-Ala-Gly in D-AlaGly within about 10 min on a chip.…”

Section: Further Chiral Selectors In Mcementioning

confidence: 96%

Progress in microchip enantioseparations

et al. 2009

View full text Add to dashboard Cite

Advances in microfluidic chips for chiral separations from 2003 to early 2009 are discussed. Microchip-based separation techniques promise higher speed, throughput, portability, less sample and reagent consumption, better environmental compatibility, reduced cost and the prospect of system integration. Microchip electrophoresis is the most promising technique for miniaturized enantioseparations and has been performed with a variety of designs and analytes, however, other formats such as microchip electrochromatography are also gaining in popularity. Microchip fabrication, chemistry and detection issues are critically discussed and highlighted. Integration of enantioseparation techniques into multifunctional microchips are currently a rapidly advancing area of research and methods are discussed that may eventually enable enantioseparations to be the part of a holistic chemical microchip.

show abstract

“…Therefore, the enantiomeric separation of NE and NPE was investigated using a different separation electrolyte. 4 The combination of the chiral crown ether 18C6H 4 and DMBCD had been used successfully for the analysis of enantiomers of small underivatized amines by CE with contactless conductivity detection [36] and also for the separation and detection of stereoisomers of di-, tri-, and tetrapeptides [34]. The chiral crown ether interacts with the amine group through hydrogen bonding, while the CD interacts with the lipophilic part of the peptides.…”

Section: Dual Chiral Selectors Using Cmbcd and Dmbcdmentioning

confidence: 99%

“…When using conductivity detection it is necessary to keep the background conductivity of the buffer low, and thus neutral CDs, or species that are weak electrolytes and neutral at the pH used, have previously been employed for the separation of amines in their protonated form, and these have also been combined with the chiral crown ether (1)-(18-crown-6)-2,3,11,12-tetracarboxylic acid in order to achieve the required separation (18C6H 4 ) [22,[33][34][35][36]. In this work, a neutral modified CD (DMBCD), and the anionic CD (carboxymethyl-b-CD or CMBCD), as well as 18C6H 4 were investigated for their separation ability for the chiral compounds of interest.…”

Section: Chiral Selectorsmentioning

confidence: 99%

Enantiomeric separation of some common controlled stimulants by capillary electrophoresis with contactless conductivity detection

et al. 2011

Self Cite

View full text Add to dashboard Cite

CE methods with capacitively coupled contactless conductivity detection (C(4)D) were developed for the enantiomeric separation of the following stimulants: amphetamine (AP), methamphetamine (MA), ephedrine (EP), pseudoephedrine (PE), norephedrine (NE) and norpseudoephedrine (NPE). Acetic acid (pH 2.5 and 2.8) was found to be the optimal background electrolyte for the CE-C(4)D system. The chiral selectors, carboxymethyl-β-cyclodextrin (CMBCD), heptakis(2,6-di-O-methyl)-β-cyclodextrin (DMBCD) and chiral crown ether (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (18C6H(4)), were investigated for their enantioseparation properties in the BGE. The use of either a single or a combination of two chiral selectors was chosen to obtain optimal condition of enantiomeric selectivity. Enantiomeric separation of AP and MA was achieved using the single chiral selector CMBCD and (hydroxypropyl)methyl cellulose (HPMC) as the modifier. A combination of the two chiral selectors, CMBCD and DMBCD and HPMC as the modifier, was required for enantiomeric separation of EP and PE. In addition, a combination of DMBCD and 18C6H(4) was successfully applied for the enantiomeric separation of NE and NPE. The detection limits of the enantiomers were found to be in the range of 2.3-5.7 μmol/L. Good precisions of migration time and peak area were obtained. The developed CE-C(4)D method was successfully applied to urine samples of athletes for the identification of enantiomers of the detected stimulants.

show abstract

Separating stereoisomers of di‐, tri‐, and tetrapeptides using capillary electrophoresis with contactless conductivity detection

Cited by 29 publications

References 68 publications

The dependence of the electrophoretic mobility of small organic ions on ionic strength and complex formation

The dependence of the electrophoretic mobility of small organic ions on ionic strength and complex formation

Progress in microchip enantioseparations

Enantiomeric separation of some common controlled stimulants by capillary electrophoresis with contactless conductivity detection

Contact Info

Product

Resources

About