Using Magnetic Levitation to Separate Mixtures of Crystal Polymorphs

Atkinson, Manza B. J.; Bwambok, David K.; Chen, Jie; Chopade, Prashant D.; Thuo, Martin M.; Mace, Charles R.; Mirica, Katherine A.; Kumar, Ashok Ashwin; Myerson, Allan S.; Whitesides, George M.

doi:10.1002/anie.201305549

Cited by 59 publications

(53 citation statements)

References 40 publications

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“…10 Due to the placement of the magnet above the container, extraction of samples separated in paramagnetic AMPS in MagLev is not as simple as extraction of objects separated in AMPS alone where a simple pipet can be used to extract samples from an interface. We have, however, previously demonstrated methods to remove objects separated by MagLev including the use of syringes and tubing with a modified container 49 and the use of a continuous flow system. 50 These methods could be applied to a system that combines MagLev and AMPS, but a low flow rate may be required to maintain a stable interface between phases in a continuous flow method.…”

Section: ■ Conclusionmentioning

confidence: 99%

Combining Step Gradients and Linear Gradients in Density

Kumar¹,

Walz

Gonidec³

et al. 2015

Anal. Chem.

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Combining aqueous multiphase systems (AMPS) and magnetic levitation (MagLev) provides a method to produce hybrid gradients in apparent density. AMPS solutions of different polymers, salts, or surfactants that spontaneously separate into immiscible but predominantly aqueous phasesoffer thermodynamically stable steps in density that can be tuned by the concentration of solutes. MagLevthe levitation of diamagnetic objects in a paramagnetic fluid within a magnetic field gradientcan be arranged to provide a near-linear gradient in effective density where the height of a levitating object above the surface of the magnet corresponds to its density; the strength of the gradient in effective density can be tuned by the choice of paramagnetic salt and its concentrations and by the strength and gradient in the magnetic field. Including paramagnetic salts (e.g., MnSO 4 or MnCl 2 ) in AMPS, and placing them in a magnetic field gradient, enables their use as media for MagLev. The potential to create large steps in density with AMPS allows separations of objects across a range of densities. The gradients produced by MagLev provide resolution over a continuous range of densities. By combining these approaches, mixtures of objects with large differences in density can be separated and analyzed simultaneously. Using MagLev to add an effective gradient in density also enables tuning the range of densities captured at an interface of an AMPS by simply changing the position of the container in the magnetic field. Further, by creating AMPS in which phases have different concentrations of paramagnetic ions, the phases can provide different resolutions in density. These results suggest that combining steps in density with gradients in density can enable new classes of separations based on density.

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Section: ■ Conclusionmentioning

confidence: 99%

Combining Step Gradients and Linear Gradients in Density

Kumar¹,

Walz

Gonidec³

et al. 2015

Anal. Chem.

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“…At equilibrium between these two forces, the object will levitate at a height which is proportional to its volumetric mass density. Magnetic levitation has been proposed for a wide range of applications, including self‐assembly and arrangement of objects, monitoring of chemical reactions and substrate binding, material characterization, bottom‐up tissue engineering, and quality control based on the volumetric mass density of the levitated object . This method allows measurements of the intrinsic cell densities and, compared to other label‐free approaches, active sorting using a magnetic field formed by two permanent magnets and does not require peripheral equipment to generate the field, reducing the overall cost.…”

Section: Introductionmentioning

confidence: 99%

Self‐Contained Handheld Magnetic Platform for Point of Care Cytometry in Biological Samples

Yenilmez

Knowlton

Tasoğlu

2016

Adv Materials Technologies

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Magnetic levitation is a powerful tool capable of distinguishing micrometerscale particles based on their densities. When a particle is suspended in a paramagnetic medium and placed in a magnetic field formed by two permanent magnets with like poles facing each other, the particle will experience two forces-a magnetic force and a buoyant force. These forces cause a particle, such as a cell, which does not necessarily have magnetic properties, to levitate at a height inversely proportional to its density. Magnetic levitation has been shown to be useful for a range of applications, including disease diagnostics, material characterization, and quality control. Here, a portable, self-contained device fully independent from a dedicated microscope or smartphone is developed to levitate particles of interest, image them using an embedded low-cost optical system and a camera module, and process the captured images in order to estimate the densities of the particles. The device is user-friendly and inexpensive, offering a great potential for rapid, on-site sample analysis such as white blood cell cytometry.

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“…Particle manipulation and subsequent separation can be achieved by the application of electromagnetic fields: a magnetic field could separate polymorphs, crystalline solids with different solid-state structures, to prepare seeds for large-scale crystallization, provided that a suitable paramagnetic medium can be found. [8] Alternatively, an electric field has been used in the successful capturing or manipulation of desired nanoparticles [9] and the assembly of colloid particles for the production of, for instance, optically tunable micropatterns, biosensors, and biofuel cells. [10][11][12] In all of these cases, the liquid phases did not contain any dissolved particle materials.…”

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confidence: 99%

Solid Separation from a Mixed Suspension through Electric‐Field‐Enhanced Crystallization

Radacsi

Kramer

et al. 2016

Angew Chem Int Ed

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This version is available at https://strathprints.strath.ac.uk/59326/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. COMMUNICATION Concomitant Solid Separation through Electric Field Enhanced CrystallizationWei W. Li, [b] Norbert Radacsi, [b] Herman J.M. Kramer, [b] Antoine E. D. M. van der Heijden [b] and Joop H. ter Horst* [a] Abstract: When applied to a pure component suspension in an apolar solvent, a strong inhomogeneous electric field induces particle movement and the particles are collected at the surface of one of the two electrodes. This new phenomenon was used to separately isolate two organic crystalline compounds, phenazine and caffeine, from their suspension of 1,4-dioxane. First, the crystals of both compounds were collected at different electrodes under the influence of the electric field. Subsequent cooling crystallization allowed the immobilization and growth of the particles on the electrodes, which were separately collected after the experiment with purities higher than 91%. This method can be further developed into a technique for crystal separation and recovery in complex multicomponent suspensions of industrial processes.Crystallization is an effective and efficient separation technology that can, in a single process step, recover the desired compounds from solutions as high purity (>99%) crystalline solids [1,2,3,4] . However, such highly purified product is hard to obtain from a multi-component solution by direct crystallization, such as the product stream from a type-I Multicomponent Reaction (MCR), [5,6] or a racemic mixture of chiral pharmaceutical compounds, [7] since a mixed suspension is a likely result. Further purification of the solid phase usually requires additional steps (see Figure 1 (a) for instance), which will inevitably lead to the loss of valuable products. Alternatively, a single crystallization step coupled with simultaneous particle separation could diminish the product loss wh...

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Using Magnetic Levitation to Separate Mixtures of Crystal Polymorphs

Cited by 59 publications

References 40 publications

Combining Step Gradients and Linear Gradients in Density

Combining Step Gradients and Linear Gradients in Density

Self‐Contained Handheld Magnetic Platform for Point of Care Cytometry in Biological Samples

Solid Separation from a Mixed Suspension through Electric‐Field‐Enhanced Crystallization

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