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Ren X, Breadmore MC, Maya F. Bidimensional Dynamic Magnetic Levitation: Sequential Separation of Microplastics by Density and Size. Anal Chem 2024; 96:3259-3266. [PMID: 38363724 DOI: 10.1021/acs.analchem.3c02918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2024]
Abstract
There is a current gap in sample preparation techniques integrating the separation of microplastics according to their different material types and particle sizes. We describe herein the Bidimensional Dynamic Magnetic Levitation (2D-MagLev) technique, enabling the resolution of mixtures of microplastics sorting them by plastic type and particle size. Separations are carried out in a bespoke flow cell sandwiched between two ring magnets and connected to programmable pumps for flow control. The first separation dimension is based on sequential increases in the concentration of a paramagnetic salt (MnCl2), enabling magnetic levitation of microplastics with determined densities. The second dimension is based on increasing flow rate gradients and maintaining constant MnCl2 concentrations. This fractionates the magnetically levitating microplastics according to their different particle sizes. Microplastics are therefore collected by their increasing density, and the particles corresponding to each density are fractionated from smaller to larger size. Using polyethylene microspheres with defined density (1.03-1.13 g cm-3) and size (98-390 μm) as microplastic mimicking materials, we investigated their optimum threshold velocities for their size fractionation, potential effects of medium viscosity and sample loading, and types of flow rate gradients (linear, step). Performing a separation using a combination of step gradients in both MnCl2 concentration and flow rate, mixtures comprising microplastics of two different densities and three different particle sizes were separated. 2D-MagLev is simple, fast, versatile, and robust, opening new avenues to facilitate the study of the environmental presence and impact of microplastics.
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Affiliation(s)
- Xinpeng Ren
- Australian Centre for Research on Separation Science, School of Natural Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia
| | - Michael C Breadmore
- Australian Centre for Research on Separation Science, School of Natural Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia
| | - Fernando Maya
- Australian Centre for Research on Separation Science, School of Natural Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia
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Xia L, Liu J, Zhu X, Liu R, Wen H, Cao Q. Asymmetric magnetic levitation for density-based measurement and analysis. Anal Chim Acta 2024; 1287:341951. [PMID: 38182357 DOI: 10.1016/j.aca.2023.341951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/25/2023] [Accepted: 10/21/2023] [Indexed: 01/07/2024]
Abstract
BACKGROUND Magnetic levitation (MagLev) based on negative magnetophoresis represents a promising technology for density-based analysis and manipulation of nonmagnetic objects. This approach has garnered considerable interest across multiple fields, such as chemistry, materials science, and biochemistry, primarily due to its inherent simplicity, precision, and cost-effectiveness. However, it is essential to recognize that frequently used MagLev configurations, including standard MagLev and axial MagLev, are not without their limitations. These configurations often struggle to strike a balance between levitation performance, ease of operation, and visibility. Therefore, it is necessary to develop a new MagLev configuration to address the aforementioned issue. RESULTS This work describes the development of an innovative MagLev, termed "asymmetric MagLev", achieved by combining a ring magnet and a cylinder magnet as up-down asymmetric magnetic field sources. The asymmetric design overcomes the physical obstacles along the centerline of the standard MagLev, offering unique open-structure advantages, including easy handling of samples, the ability to observe samples from the top or bottom, and no restrictions on the container height. Meanwhile, comparative analysis reveals a considerable enhancement in the working distance of the asymmetric MagLev without significantly sacrificing the measurement range compared to the axial MagLev. Notably, the asymmetric MagLev achieves a remarkable sensitivity of up to about 1.8 × 104 mm (g cm-3)-1, surpassing the axial MagLev by approximately 30 times. Furthermore, experimental results validate the successful application of the asymmetric MagLev in density measurement and quality detection of small-sized objects. SIGNIFICANCE This pioneering configuration represents the first utilization of up-down asymmetric magnets in the field of MagLev. Through the integration of an axially magnetized ring magnet and a cylinder magnet, the asymmetric MagLev design overcomes the limitations associated with conventional MagLev configurations. This innovative design exhibits outstanding operational capabilities and levitation performance, making it suitable for a wide range of applications in density-based measurement and analysis.
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Affiliation(s)
- Liangyu Xia
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China; State Key Laboratory of Advanced Electromagnetic Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jialuo Liu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China; State Key Laboratory of Advanced Electromagnetic Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Xinhui Zhu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China; State Key Laboratory of Advanced Electromagnetic Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Ruiqi Liu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China; State Key Laboratory of Advanced Electromagnetic Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Hao Wen
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China; State Key Laboratory of Advanced Electromagnetic Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Quanliang Cao
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China; State Key Laboratory of Advanced Electromagnetic Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
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Xia L, Liu R, Liu J, Zhu X, Ding A, Cao Q. Radial Magnetic Levitation and Its Application to Density Measurement, Separation, and Detection of Microplastics. Anal Chem 2023. [PMID: 37216472 DOI: 10.1021/acs.analchem.3c01216] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This work describes the development of radial magnetic levitation (MagLev) using two radially magnetized ring magnets to solve the problem of limited operational spaces in standard MagLev and the major shortcoming of a short working distance in axial MagLev. Interestingly and importantly, we demonstrate that for the same magnet size, this new configuration of MagLev doubles the working distance over the axial MagLev without significantly sacrificing the density measurement range, whether for linear or nonlinear analysis. Meanwhile, we develop a magnetic assembly method to fabricate the magnets for the radial MagLev, where multiple magnetic tiles with single-direction magnetization are used as assembly elements. On this basis, we experimentally demonstrate that the radial MagLev has good applicability in density-based measurement, separation, and detection and show its advantages in improving separation performance compared with the axial MagLev. The open structure of two-ring magnets and good levitation characteristics make the radial MagLev have great application potential, and the performance improvement brought by adjusting the magnetization direction of magnets provides a new perspective for the magnet design in the field of MagLev.
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Affiliation(s)
- Liangyu Xia
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Ruiqi Liu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jialuo Liu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xinhui Zhu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Anzi Ding
- Wuhan Electric Power Technical College, Wuhan 430074, China
| | - Quanliang Cao
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
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Yu J, Li D, Zhu C, Ouyang Q, Miao C, Yu H. A Magnetic Levitation System for Range/Sensitivity-Tunable Measurement of Density. SENSORS (BASEL, SWITZERLAND) 2023; 23:3955. [PMID: 37112295 PMCID: PMC10143956 DOI: 10.3390/s23083955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 06/19/2023]
Abstract
Magnetic levitation (MagLev) is a promising density-based analytical technique with numerous applications. Several MagLev structures with different levels of sensitivity and range have been studied. However, these MagLev structures can seldom satisfy the different performance requirements simultaneously, such as high sensitivity, wide measurement range, and easy operation, which have prevented them from being widely used. In this work, a tunable MagLev system was developed. It is confirmed by numerical simulation and experiments that this system possesses a high resolution down to 10-7 g/cm3 or even higher compared to the existing systems. Meanwhile, the resolution and range of this tunable system can be adjusted to meet different requirements of measurement. More importantly, this system can be operated simply and conveniently. This bundle of characteristics demonstrates that the novel tunable MagLev system could be handily applied in various density-based analyses on demand, which would greatly expand the ability of MagLev technology.
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Affiliation(s)
- Junhui Yu
- Key Laboratory of Flexible Electronics (KLOFE), School of Flexible Electronics (Future Technologies) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China
| | - Donghai Li
- Key Laboratory of Flexible Electronics (KLOFE), School of Flexible Electronics (Future Technologies) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China
| | - Chengxian Zhu
- Key Laboratory of Flexible Electronics (KLOFE), School of Flexible Electronics (Future Technologies) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China
| | - Qiran Ouyang
- Key Laboratory of Flexible Electronics (KLOFE), School of Flexible Electronics (Future Technologies) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China
| | - Chunyang Miao
- Key Laboratory of Flexible Electronics (KLOFE), School of Flexible Electronics (Future Technologies) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China
| | - Haidong Yu
- Key Laboratory of Flexible Electronics (KLOFE), School of Flexible Electronics (Future Technologies) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China
- Xi’an Institute of Flexible Electronics, Northwestern Polytechnical University, 127 West Youyi Road, Xi’an 710072, China
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