Cyclodextrins in capillary electrophoresis enantioseparations – Recent developments and applications

Scriba, Gerhard K. E.

doi:10.1002/jssc.200800095

Cited by 152 publications

(105 citation statements)

References 192 publications

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“…Since the chemical synthesis of enantiomers usually gives rise to racemic compounds, chiral separation is of utmost importance. Current approaches are based on direct gas chromatography [7] or HPLC (High Pressure Liquid Chromatography) [37], capillary electrophoresis [34], or NMR (Nuclear Magnetic Resonance) anisotropy methods [38]. They suffer from the drawbacks that they are slow and only yield endpoint results, i.e., they do not provide any information about the dynamics of the separation process.…”

Section: Left-and Right-handed Enantiomermentioning

confidence: 99%

Numerical simulation of surface acoustic wave actuated enantiomer separation by the finite element immersed boundary method

et al. 2015

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Abstract. Enantiomers are chiral objects such as chemical molecules that can be distinguished by their handedness. They typically occur as racemic compounds of left-and right-handed species which may have completely different properties. Therefore, in applications such as drug design in pharmacology, enantiomer separation is an important issue. Here, we present a new technology for enantiomer separation by surface acoustic wave generated vorticity patterns consisting of pairwise counter-rotating vortices in a carrier fluid. The enantiomers are injected onto the surface of the fluid between two counter-rotating vortices such that right-handed (left-handed) enantiomers get attracted by left-rotating (right-rotating) vortices. In particular, we are concerned with the numerical simulation of this separation process by an application of the finite element immersed boundary method which relies on the solution of a coupled system consisting of the incompressible NavierStokes equations and the equations of motion of the immersed enantiomers described with respect to an Eulerian and a Lagrangian coordinate system. For a model system of deformable, initially L-shaped enantiomers the results of the numerical simulations reveal a perfect separation.

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Section: Left-and Right-handed Enantiomermentioning

confidence: 99%

Numerical simulation of surface acoustic wave actuated enantiomer separation by the finite element immersed boundary method

et al. 2015

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“…From these reports it can be concluded that almost the entire primary rim and some of the secondary rim is sulfonated and negatively charged. Sulfonated ␤-CDs are used in chromatography and especially in capillary electrophoresis for the enantiomeric separation of compounds [12]. However, there have been very few studies carried out on the inclusion of guest molecules within the cavity of the sulfonated ␤-CDs.…”

Section: Introductionmentioning

confidence: 99%

An electrochemical study in aqueous solutions on the binding of dopamine to a sulfonated cyclodextrin host

Hendy

Breslin

2012

Electrochimica Acta

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a b s t r a c tClear evidence for the formation of a weak inclusion complex between dopamine (DA) and a sulfonated ␤-CD host in aqueous solution was obtained using a combination of electrochemical approaches. Using cyclic voltammetry, a distinct increase in the oxidation potential of DA and a reduction in the peak oxidation current were observed on adding an excess concentration of the sulfonated ␤-CD to the electrolyte solution. Equally, a clear increase in the half-wave oxidation potential of DA was observed in the presence of the sulfonated ␤-CD using rotating disc voltammetry. The association constant, K, was computed as 331.3 ± 5.8, indicating the formation of a weak inclusion complex, while a 1:1 stoichiometry for the inclusion complex was deduced from a Job's plot analysis. The rate constant for the oxidation of DA was found to decrease on formation of the inclusion complex. This was attributed to higher reorganization energy for the oxidation of the included DA. These changes in the electrochemistry of DA were not observed when an excess of the smaller sulfonated ␣-CD was added to the electrolyte, indicating that these variations are not connected with simple electrostatic interactions between the protonated DA and the anionic sulfonated groups. It is proposed that the aromatic ring of the DA molecule includes within the cyclodextrin cavity, while the protonated amine group remains outside the cavity, bound electrostatically with the anionic sulfonated groups.

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“…Chemical synthesis of chiral molecules usually produces a racemic mixture, with equal amounts of both enantiomers, and their separation based on chirality is of importance in fields ranging from agriculture to food and pharmaceutical industries. Currently favored approaches rely on gas, liquid or capillary electromigration chromatography [2], requiring costly chiral media. Thus, simpler, alternative approaches to chiral separation are desirable.…”

mentioning

confidence: 99%

Separation of Microscale Chiral Objects by Shear Flow

Marcos

Fu²,

Powers³

et al. 2009

Phys. Rev. Lett.

104

117

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We show that plane parabolic flow in a microfluidic channel causes nonmotile helically-shaped bacteria to drift perpendicular to the shear plane. Net drift results from the preferential alignment of helices with streamlines, with a direction that depends on the chirality of the helix and the sign of the shear rate. The drift is in good agreement with a model based on resistive force theory, and separation is efficient (> 80%) and fast (< 2 s). We estimate the effect of Brownian rotational diffusion on chiral separation and show how this method can be extended to separate chiral molecules.Many biochemically active molecules are naturally chiral and can only bind to target chiral molecules of a specific handedness [1]. The other enantiomer (i.e. the molecule having opposite handedness) may be inactive or cause undesirable effects. Chemical synthesis of chiral molecules usually produces a racemic mixture, with equal amounts of both enantiomers, and their separation based on chirality is of importance in fields ranging from agriculture to food and pharmaceutical industries. Currently favored approaches rely on gas, liquid or capillary electromigration chromatography [2], requiring costly chiral media. Thus, simpler, alternative approaches to chiral separation are desirable.Several alternative proposals for chiral separation exploit hydrodynamic forces. Some of these, yet untested experimentally, rely on the presence of a surface [3] or array of microvortices [4], and there has been successful chiral separation of cm-sized crystals in a rotating drum [5]. Other methods [6,7] stem from the prediction that a chiral particle in a simple shear flow experiences a lateral drift [8]. However, the feasibility of this approach has remained questionable, as measurements in Couette cells reported that the drift of mm-sized chiral objects [9] and the forces on cm-sized ones [10] differ from predictions by two orders of magnitude [9] or even in sign [10].Here we report that microscale chiral objects, three orders of magnitude smaller than previous studies [9,10], experience a lateral drift in a microfluidic shear flow and the magnitude of the drift is in agreement with our theory. Previous work has demonstrated the ability of microfluidics to separate and sort colloids by size [11], spermatozoa by motility [12], and microbes by their preference for dissolved chemicals [13]. Our method uses microchannels to sort particles by chirality. We show that an enantiomer drifts with direction determined by the local shear, demonstrate the feasibility of this method for chiral separation, and indicate how the high shear rates achievable in microchannels (> 10 6 s −1 [14]) allow it to be extended to smaller scales (< 40 nm).The origin of chirality-dependent drift at low Reynolds number can be simply understood for the case of a helix. In a shear flow, objects undergo periodic rotations known as Jeffery orbits [15]: a sphere rotates with constant angular velocity, whereas for an elongated body, such as a helix, the velocity depends on orienta...

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Cyclodextrins in capillary electrophoresis enantioseparations – Recent developments and applications

Cited by 152 publications

References 192 publications

Numerical simulation of surface acoustic wave actuated enantiomer separation by the finite element immersed boundary method

Numerical simulation of surface acoustic wave actuated enantiomer separation by the finite element immersed boundary method

An electrochemical study in aqueous solutions on the binding of dopamine to a sulfonated cyclodextrin host

Separation of Microscale Chiral Objects by Shear Flow

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