Polymeric Sulfated Amino Acid Surfactants:  A Class of Versatile Chiral Selectors for Micellar Electrokinetic Chromatography (MEKC) and MEKC-MS

Rizvi, Syed A. A.; Zheng, Jie; Apkarian, Robert P.; Dublin, Steven N.; Shamsi, Shahab A.

doi:10.1021/ac061228t

Cited by 62 publications

(74 citation statements)

References 66 publications

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“…These drawbacks were overcome by using synthetic polymeric surfactants that can work as a pseudostationary phase and provide stable electrospray (3). The polymeric surfactant was made by polymerizing three amino acidderived (L-leucinol, L-isoleucinol, L-valinol) sulfated chiral surfactants.…”

Section: Technique Developments Separation Schemesmentioning

confidence: 99%

“…Typically, in the presence of tris(2,2′-bipyridine)ruthenium(II), secondary and tertiary amines produce very strong ECL signals but a very weak signal is obtained for primary amines. To overcome lack of sensitivity for primary amines (i.e., arginine, proline, valine and leucine), they were modified with acetaldehyde prior to their CZE analysis; these modified amines produced a strong ECL response when the buffer contained Ru(bpy) 3 2+ and had LODs ranging from 0.5 to 5 fmol. A separate report described how to analyze mixtures of compounds containg primary, secondary, and tertiary amino groups.…”

Section: Detectionmentioning

confidence: 99%

“…This report combined a LED-induced fluorescence and ECL detection (76). Prior to the CE analysis, primary amines were labeled with NDA to make them detectable by fluorescence while the secondary and tertiary amines were reacted with [Ru(bpy) 3 2+ ] to make them detectable by ECL. This dual detection scheme successfully applied to detect amino acids and alkaloids in urine samples and tobacco extracts separated by CZE in borate buffer.…”

Section: Detectionmentioning

confidence: 99%

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Capillary Electrophoresis in Bioanalysis

2008

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Science reports ∼4800 hits on capillary electrophoresis (CE) including 410 reviews. Because of the prominence of CE techniques in bioanalysis, we decided make them the focus of this review and selected 200 hundred papers representing advances in this field. The selected papers cover advances in CE theory, instrumentation, and methodologies that are specific to various analytes of biological origin or relevance. The group of analytes includes nucleic acids, proteins and peptides, carbohydrates, lipids, single cells, and bioparticles. In addition, we have included advances in the use of CE to define functional assays or to investigate biomolecular interactions. The use of microfabricated devices for CE analysis was not included because this is already covered in other review. Technique Developments Separation SchemesDetermining the velocity of the electroosmotic flow (EOF) and how it changes during an electrophoretic separation is still an important research topic. A simple method for EOF measurements using so-called thermal marks was reported (1). Here, a tungsten filament caused punctual heating at the capillary wall and caused a perturbation in the electrolyte concentration. A sequence of these "thermal marks" then migrated with the EOF until each mark reached and was detected by a conductivity detector. The feasibility of using thermal marks as internal EOF standards in different separation systems was thereby demonstrated.Isoelectric focusing separates amphoteric analytes such as proteins or peptides by the differences in their isoelectric points. Most of the reports on capillary isoelectric focusing (cIEF) describe an initial focusing phase after which the focused zones are mobilized and detected. A dynamic cIEF method for protein analysis was reported (2). This technique made it possible to control each protein's position and focused width by moving the pH gradient within the capillary through manipulation of the electric fields. An important advantage of this approach is the capability of collecting focused analytes from the central section, suggesting that there may be great potential for introducing selectively focused proteins to a second separation dimension such as LC or CE.Micellar electrokinetic capillary chromatography (MEKC) is typically incompatible with electrospray mass spectrometry (ESI-MS) because the nonvolatile surfactants in the micellar phase result in complicated adduct formation and loss of sensitivity during the electrospray process and because the presence of the organic solvent needed for electrospray may cause instability in the micellar phase. These drawbacks were overcome by using synthetic polymeric surfactants that can work as a pseudostationary phase and provide stable electrospray (3). The polymeric surfactant was made by polymerizing three amino acidderived (L-leucinol, L-isoleucinol, L-valinol) sulfated chiral surfactants. These polymeric

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Section: Technique Developments Separation Schemesmentioning

confidence: 99%

Section: Detectionmentioning

confidence: 99%

Section: Detectionmentioning

confidence: 99%

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Capillary Electrophoresis in Bioanalysis

2008

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“…On the other hand, polymeric surfactants (also called molecular micelles or micelle polymers) are very attractive as alternative pseudostationary phases to conventional micelles for the coupling of the MEKC separation mode with ESI-MS [44][45][46]. They provide several advantages over conventional micelles for this hyphenation [44,45]: (i) the covalent bonds between surfactant monomers are difficult to ionize in the electrospray resulting in less-background noise from surfactant monomers of low molecular weights in MEKC-MS applications, (ii) micellar solutions can be used at any polymer concentration due to zero CMC, consequently higher S/N are observed in MEKC-ESI-MS, and (iii) polymeric surfactants have lower surface activity and lower volatility, and are stable in the presence of a high content of organic modifier in the BGE, which also tends to enhance the ESI-MS intensity.…”

Section: End-column Detection In Chiral Analysis By Cementioning

confidence: 99%

Sensitive chiral analysis by CE: An update

et al. 2007

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Sensitive chiral analysis by CE: An updateA general view of the different strategies used in the last years to enhance the detection sensitivity in chiral analysis by CE is provided in this article. With this purpose and in order to update the previous review by García-Ruiz et al., the articles appeared on this subject from January 2005 to March 2007 are considered. Three were the main strategies employed to increase the detection sensitivity in chiral analysis by CE: (i) the use of off-line sample treatment techniques, (ii) the employment of in-capillary preconcentration techniques based on electrophoretic principles, and (iii) the use of alternative detection systems to the widely employed on-column UV-Vis absorption detection. Combinations of two or three of the above-mentioned strategies gave rise to adequate concentration detection limits up to 10 210 M enabling enantiomer analysis in a variety of real samples including complex biological matrices.

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“…Molecular micelles, also known as polymeric surfactants, have been successfully used in numerous analytical approaches as chiral discriminators for the analysis of a variety of chiral molecules of different molecular size and polarity [19][20][21][22][23][24][25]. As an example, micellar electrokinetic chromatography (MEKC), a widely used mode of capillary electrophoresis, has become a very popular method for chiral analysis using both monomeric and polymeric surfactants.…”

Section: Introductionmentioning

confidence: 99%

Determination of Enantiomeric Compositions of Analytes Using Novel Fluorescent Chiral Molecular Micelles and Steady State Fluorescence Measurements

et al. 2007

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Novel fluorescent chiral molecular micelles (FCMMs) were synthesized, characterized, and employed as chiral selectors for enantiomeric recognition of non-fluorescent chiral molecules using steady state fluorescence spectroscopy. The sensitivity of the fluorescence technique allowed for investigation of low concentrations of chiral selector (3.0×10 −5 M) and analyte (5.0×10 −6 M) to be used in these studies. The chiral interactions of glucose, tartaric acid, and serine in the presence of, and poly(sodium N-undecanoyl-L-phenylalininate) [poly-SUF] were based on diastereomeric complex formation. Poly-L-SUW had a significant fluorescence emission spectral difference as compared to poly-L-SUY and poly-L-SUF for the enantiomeric recognition of glucose, tartaric acid, and serine. Studies with the hydrophobic molecule α-pinene suggested that poly-L-SUY and poly-L-SUF had better chiral discrimination ability for hydrophobic analytes as compared to hydrophilic analytes. Partial-least-squares regression modeling (PLS-1) was used to correlate changes in the fluorescence emission spectra of poly-L-SUW due to varying enantiomeric compositions of glucose, tartaric acid, and serine for a set of calibration samples. Validation of the calibration regression models was determined by use of a set of independently prepared samples of the same concentration of chiral selector and analyte with varying enantiomeric composition. Prediction ability was evaluated by use of the root-mean-square percent relative error (RMS%RE) and was found to range from 2.04 to 4.06%.

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Polymeric Sulfated Amino Acid Surfactants: A Class of Versatile Chiral Selectors for Micellar Electrokinetic Chromatography (MEKC) and MEKC-MS

Cited by 62 publications

References 66 publications

Capillary Electrophoresis in Bioanalysis

Capillary Electrophoresis in Bioanalysis

Sensitive chiral analysis by CE: An update

Determination of Enantiomeric Compositions of Analytes Using Novel Fluorescent Chiral Molecular Micelles and Steady State Fluorescence Measurements

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