1
|
Seo J, Ha S, Kim SJ. Investigation of Operational Parameters for Nanoelectrokinetic Purification and Preconcentration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:16443-16453. [PMID: 39048092 DOI: 10.1021/acs.langmuir.4c01773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
This work reports on experimental investigations into the operational parameters of nanoelectrokinetic purification and preconcentration, especially utilizing on ion concentration polarization (ICP). ICP as a nanoscale electrokinetic phenomenon has demonstrated promising advances in various fields utilizing an ion depletion zone (IDZ) with a steep electric field gradient inside the ICP layer. However, the inevitable electrokinetic instability occurring within the IDZ has posed a challenge in operating the ICP system stably. To address the need for a stable and efficient ICP operation in various devices and applications, we propose an operational strategy along with conducted research to determine optimal operating ranges. In order to investigate the operational parameters, a unit voltage (VTH) is introduced as the threshold for initiating ICP. We examined the applicability of VTH across various operating ranges to ensure its effectiveness and versatility. In ICP purification, we categorize three modes (steady, burst, and unsteady) based on IDZ expansion and stability under varying VTH and flow rate conditions, presenting optimal operational conditions that minimize the voltage margin. In ICP preconcentration, a systematic investigation is conducted to observe the influence of background electrolyte concentration and voltage conditions on preconcentration efficiency, offering insights into the correlation between preconcentration factor, electrical conditions, and preconcentration time. Therefore, this research would contribute to the practical understanding of nanoelectrokinetics, providing insight into experimental designs. These findings are expected to offer valuable guidance to researchers aiming to utilize ICP's potential across a spectrum of applications, from purification to preconcentration, in the realm of micro/nanofluidic systems.
Collapse
Affiliation(s)
- Joowon Seo
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Sungjae Ha
- ProvaLabs, Inc., Seoul 08826, Republic of Korea
| | - Sung Jae Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Republic of Korea
- SOFT Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
- Inter-University Semiconductor Research Center, Seoul National University, Seoul 08826, Republic of Korea
| |
Collapse
|
2
|
Sun Z, Ma C, Yu C, Li Z. Microplastic separation and enrichment in microchannels under derivative electric field gradient by bipolar electrode reactions. Sci Rep 2024; 14:4626. [PMID: 38409340 PMCID: PMC10897390 DOI: 10.1038/s41598-024-54921-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 02/18/2024] [Indexed: 02/28/2024] Open
Abstract
The decomposed plastic products in the natural environment evolve into tiny plastic particles with characteristics such as small size, lightweight, and difficulty in removal, resulting in a significant pollution issue in aquatic environments. Significant progress has been made in microplastic separation technology benefiting from microfluidic chips in recent years. Based on the mechanisms of microfluidic control technology, this study investigates the enrichment and separation mechanisms of polystyrene particles in an unbuffered solution. The Faraday reaction caused by the bipolar electrodes changes the electric field gradient and improves the separation efficiency. We also propose an evaluation scheme to measure the separation efficiency. Finite element simulations are conducted to parametrically analyze the influence of applied voltages, channel geometry, and size of electrodes on plastic particle separation. The numerical cases indicate that the electrode-installed microfluidic channels separate microplastic particles effectively and precisely. The electrodes play an important role in local electric field distribution and trigger violent chemical reactions. By optimizing the microchannel structure, applied voltages, and separation channel angle, an optimal solution for separating microplastic particles can be found. This study could supply some references to control microplastic pollution in the future.
Collapse
Affiliation(s)
- Zhenrong Sun
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, 300401, China
| | - Chicheng Ma
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, 300401, China.
| | - Chengjiao Yu
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, 300401, China.
| | - Zirui Li
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, 300401, China
| |
Collapse
|
3
|
Kamel AH, Hefnawy A, Hazeem LJ, Rashdan SA, Abd-Rabboh HSM. Current perspectives, challenges, and future directions in the electrochemical detection of microplastics. RSC Adv 2024; 14:2134-2158. [PMID: 38205235 PMCID: PMC10777194 DOI: 10.1039/d3ra06755f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
Microplastics (5 μm) are a developing threat that contaminate every environmental compartment. The detection of these contaminants is undoubtedly an important topic of study because of their high potential to cause harm to ecosystems. For many years, scientists have been assiduously striving to surmount the obstacle of detection restrictions and minimize the likelihood of receiving results that are either false positives or false negatives. This study covers the current state of electrochemical sensing technology as well as its application as a low-cost analytical platform for the detection and characterization of novel contaminants. Examples of detection mechanisms, electrode modification procedures, device configuration, and performance are given to show how successful these approaches are for monitoring microplastics in the environment. Additionally included are the recent developments in nanoimpact techniques. Compared to electrochemical methods for microplastic remediation, the use of electrochemical sensors for microplastic detection has received very little attention. With an overview of microplastic electrochemical sensors, this review emphasizes the promise of existing electrochemical remediation platforms toward sensor design and development. In order to enhance the monitoring of these substances, a critical assessment of the requirements for future research, challenges associated with detection, and opportunities is provided. In addition to-or instead of-the now-in-use laboratory-based analytical equipment, these technologies can be utilized to support extensive research and manage issues pertaining to microplastics in the environment and other matrices.
Collapse
Affiliation(s)
- Ayman H Kamel
- Department, College of Science, University of Bahrain Zallaq 32038 Kingdom of Bahrain
- Department of Chemistry, Faculty of Science, Ain Shams University Cairo 11566 Egypt
| | - A Hefnawy
- Department, College of Science, University of Bahrain Zallaq 32038 Kingdom of Bahrain
- Department of Materials Science, Institute of Graduate Studies and Research, Alexandria University El-Shatby Alexandria 21526 Egypt
| | - Layla J Hazeem
- Department of Biology, College of Science, University of Bahrain Zallaq 32038 Bahrain
| | - Suad A Rashdan
- Department, College of Science, University of Bahrain Zallaq 32038 Kingdom of Bahrain
| | - Hisham S M Abd-Rabboh
- Chemistry Department, Faculty of Science, King Khalid University Abha 62529 Saudi Arabia
| |
Collapse
|
4
|
Berzina B, Peramune U, Kim S, Saurabh K, Claus EL, Strait ME, Ganapathysubramanian B, Anand RK. Electrokinetic Enrichment and Label-Free Electrochemical Detection of Nucleic Acids by Conduction of Ions along the Surface of Bioconjugated Beads. ACS Sens 2023; 8:1173-1182. [PMID: 36800317 DOI: 10.1021/acssensors.2c02480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
In this paper, we report a method to integrate the electrokinetic pre-enrichment of nucleic acids within a bed of probe-modified microbeads with their label-free electrochemical detection. In this detection scheme, hybridization of locally enriched target nucleic acids to the beads modulates the conduction of ions along the bead surfaces. This is a fundamental advancement in that this mechanism is similar to that observed in nanopore sensors, yet occurs in a bed of microbeads with microscale interstices. In application, this approach has several distinct advantages. First, electrokinetic enrichment requires only a simple DC power supply, and in combination with nonoptical detection, it makes this method amenable to point-of-care applications. Second, the sensor is easy to fabricate and comprises a packed bed of commercially available microbeads, which can be readily modified with a wide range of probe types, thereby making this a versatile platform. Finally, the sensor is highly sensitive (picomolar) despite the modest 100-fold pre-enrichment we employ here by faradaic ion concentration polarization (fICP). Further gains are anticipated under conditions for fICP focusing that are known to yield higher enrichment factors (up to 100,000-fold enrichment). Here, we demonstrate the detection of 3.7 pM single-stranded DNA complementary to the bead-bound oligoprobe, following a 30 min single step of enrichment and hybridization. Our results indicate that a shift in the slope of a current-voltage curve occurs upon hybridization and that this shift is proportional to the logarithm of the concentration of target DNA. Finally, we investigate the proposed mechanism of sensing by developing a numerical simulation that shows an increase in ion flux through the bed of insulating beads, given the changes in surface charge and zeta potential, consistent with our experimental conditions.
Collapse
Affiliation(s)
- Beatrise Berzina
- The Department of Chemistry, Iowa State University, 1605 Gilman Hall, 2415 Osborn Drive, Ames, Iowa 50011-1021, United States
| | - Umesha Peramune
- The Department of Chemistry, Iowa State University, 1605 Gilman Hall, 2415 Osborn Drive, Ames, Iowa 50011-1021, United States
| | - Sungu Kim
- The Department of Chemistry, Iowa State University, 1605 Gilman Hall, 2415 Osborn Drive, Ames, Iowa 50011-1021, United States
- The Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, 2529 Union Drive, Ames, Iowa 50011-2030, United States
| | - Kumar Saurabh
- The Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, 2529 Union Drive, Ames, Iowa 50011-2030, United States
| | - Echo L Claus
- The Department of Chemistry, Iowa State University, 1605 Gilman Hall, 2415 Osborn Drive, Ames, Iowa 50011-1021, United States
| | - Madison E Strait
- The Department of Chemistry, Iowa State University, 1605 Gilman Hall, 2415 Osborn Drive, Ames, Iowa 50011-1021, United States
| | - Baskar Ganapathysubramanian
- The Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, 2529 Union Drive, Ames, Iowa 50011-2030, United States
| | - Robbyn K Anand
- The Department of Chemistry, Iowa State University, 1605 Gilman Hall, 2415 Osborn Drive, Ames, Iowa 50011-1021, United States
| |
Collapse
|
5
|
Broccoli A, Vollertsen AR, Roels P, van Vugt A, van den Berg A, Odijk M. Nanoparticle Printing for Microfluidic Applications: Bipolar Electrochemistry and Localized Raman Sensing Spots. MICROMACHINES 2023; 14:453. [PMID: 36838154 PMCID: PMC9967861 DOI: 10.3390/mi14020453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
The local integration of metal nanoparticle films on 3D-structured polydimethylsiloxane (PDMS)-based microfluidic devices is of high importance for applications including electronics, electrochemistry, electrocatalysis, and localized Raman sensing. Conventional processes to locally deposit and pattern metal nanoparticles require multiple steps and shadow masks, or access to cleanroom facilities, and therefore, are relatively imprecise, or time and cost-ineffective. As an alternative, we present an aerosol-based direct-write method, in which patterns of nanoparticles generated via spark ablation are locally printed with sub-mm size and precision inside of microfluidic structures without the use of lithography or other masking methods. As proof of principle, films of Pt or Ag nanoparticles were printed in the chambers of a multiplexed microfluidic device and successfully used for two different applications: Screening electrochemical activity in a high-throughput fashion, and localized sensing of chemicals via surface-enhanced Raman spectroscopy (SERS). The versatility of the approach will enable the generation of functional microfluidic devices for applications that include sensing, high-throughput screening platforms, and microreactors using catalytically driven chemical conversions.
Collapse
Affiliation(s)
- Alessia Broccoli
- BIOS Lab on a Chip Group, MESA+ Institute for Nanotechnology, Max Planck Center for Complex Fluid Dynamics, University of Twente, 7500 AE Enschede, The Netherlands
| | - Anke R. Vollertsen
- Department of Applied Stem Cell Technologies, TechMed Centre, University of Twente, 7500 AE Enschede, The Netherlands
| | | | | | - Albert van den Berg
- BIOS Lab on a Chip Group, MESA+ Institute for Nanotechnology, Max Planck Center for Complex Fluid Dynamics, University of Twente, 7500 AE Enschede, The Netherlands
| | - Mathieu Odijk
- BIOS Lab on a Chip Group, MESA+ Institute for Nanotechnology, Max Planck Center for Complex Fluid Dynamics, University of Twente, 7500 AE Enschede, The Netherlands
| |
Collapse
|
6
|
Thompson JR, Crooks RM. Electrokinetic separation techniques for studying nano- and microplastics. Chem Sci 2022; 13:12616-12624. [PMID: 36519045 PMCID: PMC9645370 DOI: 10.1039/d2sc04019k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/14/2022] [Indexed: 03/07/2024] Open
Abstract
In recent years, microplastics have been found in seawater, soil, food, and even human blood and tissues. The ubiquity of microplastics is alarming, but the health and environmental impacts of microplastics are just beginning to be understood. Accordingly, sampling, separating, and quantifying exposure to microplastics to devise a total risk assessment is the focus of ongoing research. Unfortunately, traditional separation methods (i.e., size- and density-based methods) unintentionally exclude the smallest microplastics (<10 μm). Limited data about the smallest microplastics is problematic because they are likely the most pervasive and have distinct properties from their larger plastic counterparts. To that end, in this Perspective, we discuss using electrokinetic methods for separating the smallest microplastics. Specifically, we describe three methods for forming electric field gradients, discuss key results within the field for continuously separating microplastics, and lastly discuss research avenues which we deem critical for advancing electrokinetic separation platforms for targeting the smallest microplastics.
Collapse
Affiliation(s)
- Jonathan R Thompson
- Department of Chemistry and Texas Materials Institute, The University of Texas at Austin 105 E. 24th St., Stop A5300 Austin Texas 78712-1224 USA +1-512-475-8674
| | - Richard M Crooks
- Department of Chemistry and Texas Materials Institute, The University of Texas at Austin 105 E. 24th St., Stop A5300 Austin Texas 78712-1224 USA +1-512-475-8674
| |
Collapse
|
7
|
Chen Z, Wei W, Liu X, Ni BJ. Emerging electrochemical techniques for identifying and removing micro/nanoplastics in urban waters. WATER RESEARCH 2022; 221:118846. [PMID: 35841793 DOI: 10.1016/j.watres.2022.118846] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/07/2022] [Accepted: 07/09/2022] [Indexed: 05/26/2023]
Abstract
The ubiquitous micro/nanoplastics (MPs/NPs) in urban waters are priority pollutants due to their toxic effects on living organisms. Currently, great efforts have been made to realize a plastic-free urban water system, and the identification and removal of MPs/NPs are two primary issues. Among diverse methods, emerging electrochemical techniques have gained growing interests owing to their facile implementation, high efficiency, eco-compatibility, onsite operation, etc. Herein, recent progress in the electrochemical identification and removal of MPs/NPs in urban waters are comprehensively reviewed. The electrochemical sensing of MPs/NPs and their released pollutants (e.g., bisphenol A (BPA)) has been analyzed, and the sensing principles and the featured electrochemical devices/electrodes are examined. Afterwards, recent applications of electrochemical methods (i.e., electrocoagulation, electroadsorption, electrokinetic separation and electrochemical degradation) in MPs/NPs removal are discussed in detail. The influences of critical parameters (e.g., plastics' property, current density and electrolyte) in the electrochemical identification and removal of MPs/NPs are also analyzed. Finally, the current challenges and prospects in electrochemical sensing and removal of MPs/NPs in urban waters are elaborated. This review would advance efficient electrochemical technologies for future MPs/NPs pollutions management in urban waters.
Collapse
Affiliation(s)
- Zhijie Chen
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia
| | - Xiaoqing Liu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia.
| |
Collapse
|
8
|
Thompson JR, Crooks RM. Enriching Cations Using Electric Field Gradients Generated by Bipolar Electrodes in the Absence of Buffer. ChemElectroChem 2022. [DOI: 10.1002/celc.202200251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Jonathan R. Thompson
- Department of Chemistry and Texas Materials Institute The University of Texas at Austin 105 E. 24th St., Stop A5300 Austin Texas 78712-1224 United States
| | - Richard M. Crooks
- Department of Chemistry and Texas Materials Institute The University of Texas at Austin 105 E. 24th St., Stop A5300 Austin Texas 78712-1224 United States
| |
Collapse
|
9
|
Wang K, Behdani B, Silvera Batista CA. Visualization of Concentration Gradients and Colloidal Dynamics under Electrodiffusiophoresis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:5663-5673. [PMID: 35467877 DOI: 10.1021/acs.langmuir.2c00252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In this work, we present an experimental study of the dynamics of charged colloids under direct currents and gradients of chemical species (electrodiffusiophoresis). In our approach, we simultaneously visualize the development of concentration polarization and the ensuing dynamics of charged colloids near electrodes. With the aid of confocal microscopy and fluorescent probes, we show that the passage of current through water confined between electrodes, separated about a hundred microns, results in significant pH gradients. Depending on the current density and initial conditions, steep pH gradients develop, thus becoming a significant factor in the behavior of charged colloids. Furthermore, we show that steep pH gradients induce the focusing of charged colloids away from both electrodes. Our results provide the experimental basis for further development of models of electrodiffusiophoresis and the design of non-equilibrium strategies for the fabrication of advanced materials.
Collapse
Affiliation(s)
- Kun Wang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Behrouz Behdani
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Carlos A Silvera Batista
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
- Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States
| |
Collapse
|
10
|
Park S, Sabbagh B, Abu-Rjal R, Yossifon G. Digital microfluidics-like manipulation of electrokinetically preconcentrated bioparticle plugs in continuous-flow. LAB ON A CHIP 2022; 22:814-825. [PMID: 35080550 DOI: 10.1039/d1lc00864a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Herein, we demonstrate digital microfluidics-like manipulations of preconcentrated biomolecule plugs within a continuous flow that is different from the commonly known digital microfluidics involving discrete (i.e. droplets) media. This is realized using one- and two-dimensional arrays of individually addressable ion-permselective membranes with interconnecting microfluidic channels. The location of powered electrodes, dictates which of the membranes are active and generates either enrichment/depletion diffusion layers, which, in turn, control the location of the preconcentrated plug. An array of such powered membranes enables formation of multiple preconcentrated plugs of the same biosample as well as of preconcentrated plugs of multiple biosample types introduced via different inlets in a selective manner. Moreover, digital-microfluidics operations such as up-down and left-right translation, merging, and splitting, can be realized, but on preconcentrated biomolecule plugs instead of on discrete droplets. This technology, based on nanoscale electrokinetics of ion transport through permselective medium, opens future opportunities for smart and programmable digital-like manipulations of preconcentrated biological particle plugs for various on-chip biological applications.
Collapse
Affiliation(s)
- Sinwook Park
- Faculty of Mechanical Engineering, Micro- and Nanofluidics Laboratory, Technion - Israel Institute of Technology, Technion City 3200000, Israel.
| | - Barak Sabbagh
- Faculty of Mechanical Engineering, Micro- and Nanofluidics Laboratory, Technion - Israel Institute of Technology, Technion City 3200000, Israel.
| | - Ramadan Abu-Rjal
- Faculty of Mechanical Engineering, Micro- and Nanofluidics Laboratory, Technion - Israel Institute of Technology, Technion City 3200000, Israel.
| | - Gilad Yossifon
- Faculty of Mechanical Engineering, Micro- and Nanofluidics Laboratory, Technion - Israel Institute of Technology, Technion City 3200000, Israel.
| |
Collapse
|
11
|
Berzina B, Kim S, Peramune U, Saurabh K, Ganapathysubramanian B, Anand RK. Out-of-plane faradaic ion concentration polarization: stable focusing of charged analytes at a three-dimensional porous electrode. LAB ON A CHIP 2022; 22:573-583. [PMID: 35023536 DOI: 10.1039/d1lc01011e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Ion concentration polarization (ICP) accomplishes preconcentration for bioanalysis by localized depletion of electrolyte ions, thereby generating a gradient in electric field strength that facilitates electrokinetic focusing of charged analytes by their electromigration against opposing fluid flow. Such ICP focusing has been shown to accomplish up to a million-fold enrichment of nucleic acids and proteins in single-stage preconcentrators. However, the rate at which the sample volume is swept is limited, requiring several hours to achieve these high enrichment factors. This limitation is caused by two factors. First, an ion depleted zone (IDZ) formed at a planar membrane or electrode may not extend across the full channel cross section under the flow rate employed for focusing, thereby allowing the analyte to "leak" past the IDZ. Second, within the IDZ, large fluid vortices lead to mixing, which decreases the efficiency of analyte enrichment and worsens with increased channel dimensions. Here, we address these challenges with faradaic ICP (fICP) at a three-dimensional (3D) electrode comprising metallic microbeads. This 3D-electrode distributes the IDZ, and therefore, the electric field gradient utilized for counter-flow focusing across the full height of the fluidic channel, and its large area, microstructured surface supports smaller vortices. An additional bed of insulating microbeads restricts flow patterns and supplies a large area for surface conduction of ions through the IDZ. Finally, the resistance of this secondary bed enhances focusing by locally strengthening sequestering forces. This easy-to-build platform lays a foundation for the integration of enrichment with user-defined packed bed and electrode materials.
Collapse
Affiliation(s)
- Beatrise Berzina
- The Department of Chemistry, Iowa State University, 2415 Osborn Drive, 1605 Gilman Hall, Ames, Iowa 50011-1021, USA.
| | - Sungu Kim
- The Department of Chemistry, Iowa State University, 2415 Osborn Drive, 1605 Gilman Hall, Ames, Iowa 50011-1021, USA.
- The Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, 2529 Union Drive, Ames, Iowa 50011-2030, USA
| | - Umesha Peramune
- The Department of Chemistry, Iowa State University, 2415 Osborn Drive, 1605 Gilman Hall, Ames, Iowa 50011-1021, USA.
| | - Kumar Saurabh
- The Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, 2529 Union Drive, Ames, Iowa 50011-2030, USA
| | - Baskar Ganapathysubramanian
- The Department of Mechanical Engineering, Iowa State University, 2043 Black Engineering, 2529 Union Drive, Ames, Iowa 50011-2030, USA
| | - Robbyn K Anand
- The Department of Chemistry, Iowa State University, 2415 Osborn Drive, 1605 Gilman Hall, Ames, Iowa 50011-1021, USA.
| |
Collapse
|
12
|
Krishnamurthy A, Anand RK. Recent advances in microscale extraction driven by ion concentration polarization. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
13
|
The Bipolar Mode of One‐Step Plasma Electrochemical Synthesis of Few Layer Graphene Structures Decorated with Transition Metal Oxides. ChemistrySelect 2021. [DOI: 10.1002/slct.202103830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
14
|
Thompson JR, Wilder LM, Crooks RM. Filtering and continuously separating microplastics from water using electric field gradients formed electrochemically in the absence of buffer. Chem Sci 2021; 12:13744-13755. [PMID: 34760159 PMCID: PMC8549819 DOI: 10.1039/d1sc03192a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 09/22/2021] [Indexed: 11/21/2022] Open
Abstract
Here we use experiments and finite element simulations to investigate the electrokinetics within straight microchannels that contain a bipolar electrode and an unbuffered electrolyte solution. Our findings indicate that in the presence of a sufficiently high electric field, water electrolysis proceeds at the bipolar electrode and leads to variations in both solution conductivity and ionic current density along the length of the microchannel. The significance of this finding is twofold. First, the results indicate that both solution conductivity and ionic current density variations significantly contribute to yield sharp electric field gradients near the bipolar electrode poles. The key point is that ionic current density variations constitute a fundamentally new mechanism for forming electric field gradients in solution. Second, we show that the electric field gradients that form near the bipolar electrode poles in unbuffered solution are useful for continuously separating microplastics from water in a bifurcated microchannel. This result expands the potential scope of membrane-free separations using bipolar electrodes. Water electrolysis at a bipolar electrode in the absence of buffer forms electric field gradients in a fundamentally new way. These electric field gradients are useful for continuously separating microplastics from water.![]()
Collapse
Affiliation(s)
- Jonathan R Thompson
- Department of Chemistry, Texas Materials Institute, The University of Texas at Austin 105 E. 24th St., Stop A5300 Austin Texas 78712-1224 USA +1-512-475-8674
| | - Logan M Wilder
- Department of Chemistry, Texas Materials Institute, The University of Texas at Austin 105 E. 24th St., Stop A5300 Austin Texas 78712-1224 USA +1-512-475-8674
| | - Richard M Crooks
- Department of Chemistry, Texas Materials Institute, The University of Texas at Austin 105 E. 24th St., Stop A5300 Austin Texas 78712-1224 USA +1-512-475-8674
| |
Collapse
|
15
|
Rius-Ayra O, Biserova-Tahchieva A, LLorca-Isern N. Surface-functionalised materials for microplastic removal. MARINE POLLUTION BULLETIN 2021; 167:112335. [PMID: 33839572 DOI: 10.1016/j.marpolbul.2021.112335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/28/2021] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
Microplastic (MP) pollution is a matter of great concern attracting increasing attention due to its adverse effects on the environment. Different technologies and methodologies have been developed to remove these pollutants. Herein, we focus on a promising environmental solution that involves surface modification to change the wettability properties of MPs or solid materials by conferring superhydrophobicity and superoleophilicity to increase the selectivity for MP separation. Both processes can be used to selectively separate MPs because of the changes in the wettable properties of the MP or by changing the oil used in the case of superhydrophobic surfaces. We show two distinct methods based on changing the wettability properties of surfaces that could lead to innovative and environmental applications. We also discuss some of the challenges that need to be overcome.
Collapse
Affiliation(s)
- O Rius-Ayra
- CPCM Departament de Ciència dels Materials i Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1 - 11, 08028 Barcelona, Spain.
| | - A Biserova-Tahchieva
- CPCM Departament de Ciència dels Materials i Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1 - 11, 08028 Barcelona, Spain
| | - N LLorca-Isern
- CPCM Departament de Ciència dels Materials i Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1 - 11, 08028 Barcelona, Spain
| |
Collapse
|
16
|
Blevins MG, Allen HL, Colson BC, Cook AM, Greenbaum AZ, Hemami SS, Hollmann J, Kim E, LaRocca AA, Markoski KA, Miraglia P, Mott VL, Robberson WM, Santos JA, Sprachman MM, Swierk P, Tate S, Witinski MF, Kratchman LB, Michel APM. Field-Portable Microplastic Sensing in Aqueous Environments: A Perspective on Emerging Techniques. SENSORS (BASEL, SWITZERLAND) 2021; 21:3532. [PMID: 34069517 PMCID: PMC8160859 DOI: 10.3390/s21103532] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/27/2021] [Accepted: 04/28/2021] [Indexed: 11/28/2022]
Abstract
Microplastics (MPs) have been found in aqueous environments ranging from rural ponds and lakes to the deep ocean. Despite the ubiquity of MPs, our ability to characterize MPs in the environment is limited by the lack of technologies for rapidly and accurately identifying and quantifying MPs. Although standards exist for MP sample collection and preparation, methods of MP analysis vary considerably and produce data with a broad range of data content and quality. The need for extensive analysis-specific sample preparation in current technology approaches has hindered the emergence of a single technique which can operate on aqueous samples in the field, rather than on dried laboratory preparations. In this perspective, we consider MP measurement technologies with a focus on both their eventual field-deployability and their respective data products (e.g., MP particle count, size, and/or polymer type). We present preliminary demonstrations of several prospective MP measurement techniques, with an eye towards developing a solution or solutions that can transition from the laboratory to the field. Specifically, experimental results are presented from multiple prototype systems that measure various physical properties of MPs: pyrolysis-differential mobility spectroscopy, short-wave infrared imaging, aqueous Nile Red labeling and counting, acoustophoresis, ultrasound, impedance spectroscopy, and dielectrophoresis.
Collapse
Affiliation(s)
- Morgan G. Blevins
- MIT-WHOI Joint Program in Oceanography/Applied Ocean Science & Engineering, Cambridge and Woods Hole, MA 02543, USA; (M.G.B.); (B.C.C.)
- Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Harry L. Allen
- Emergency Response Office, Superfund Division, U.S. EPA Region 9, San Francisco, CA 94105, USA;
| | - Beckett C. Colson
- MIT-WHOI Joint Program in Oceanography/Applied Ocean Science & Engineering, Cambridge and Woods Hole, MA 02543, USA; (M.G.B.); (B.C.C.)
- Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Anna-Marie Cook
- Kamilo, Inc., Former U.S. EPA Region 9, San Francisco, CA 94108, USA;
| | - Alexandra Z. Greenbaum
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Sheila S. Hemami
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115, USA;
| | - Joseph Hollmann
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Ernest Kim
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Ava A. LaRocca
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Kenneth A. Markoski
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Peter Miraglia
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Vienna L. Mott
- Draper, Bioengineering Division, Cambridge, MA 02139, USA;
| | | | - Jose A. Santos
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Melissa M. Sprachman
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Patricia Swierk
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Steven Tate
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Mark F. Witinski
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Louis B. Kratchman
- The Charles Stark Draper Laboratory Inc., Cambridge, MA 02139, USA; (A.Z.G.); (J.H.); (E.K.); (A.A.L.); (K.A.M.); (P.M.); (J.A.S.); (M.M.S.); (P.S.); (S.T.); (M.F.W.)
| | - Anna P. M. Michel
- Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| |
Collapse
|
17
|
Rius-Ayra O, Llorca-Isern N. A robust and anticorrosion non-fluorinated superhydrophobic aluminium surface for microplastic removal. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 760:144090. [PMID: 33348156 DOI: 10.1016/j.scitotenv.2020.144090] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/10/2020] [Accepted: 11/22/2020] [Indexed: 05/26/2023]
Abstract
Solid particulate pollutants such as microplastics constitute a global environmental issue in the 21st century. Many studies are exploring ways of removing these particles from marine environments such as seas and oceans. Here, we present a superhydrophobic surface obtained by combining anodisation and the liquid-phase deposition of lauric acid. The superhydrophobic surface was examined by field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) to elucidate its hierarchical structure and wetting state, while time-of-flight secondary ion mass spectrometry (TOF-SIMS) and high-resolution X-ray photoelectron spectroscopy (HR-XPS) were applied to identify the chemical composition of the surface, which revealed that aluminium laurate decreased the surface free energy. As microplastics are usually found in saline water, it was important to study the anticorrosion properties of the surface. Polarisation curves of the anodised surface showed excellent anticorrosion properties in 3.5 wt% NaCl aqueous solution, which was enhanced by the superhydrophobic properties when the aluminium surface was anodised for 60 min. The functionalised surface was superhydrophobic (154°) and superoleophilic (0°). These wetting properties allowed the surface to remove microplastics from the NaCl aqueous solution with an efficiency higher than 99%. Thus, we present a novel application of a superhydrophobic and anticorrosive surface in the removal of microplastics. This has not been reported previously and provides a new scope for superwettable materials and their environmental applications.
Collapse
Affiliation(s)
- Oriol Rius-Ayra
- CPCM, Departament de Ciència dels Materials i Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.
| | - Nuria Llorca-Isern
- CPCM, Departament de Ciència dels Materials i Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| |
Collapse
|
18
|
Beriot N, Peek J, Zornoza R, Geissen V, Huerta Lwanga E. Low density-microplastics detected in sheep faeces and soil: A case study from the intensive vegetable farming in Southeast Spain. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:142653. [PMID: 33069476 DOI: 10.1016/j.scitotenv.2020.142653] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 09/10/2020] [Accepted: 09/24/2020] [Indexed: 06/11/2023]
Abstract
One of the main sources of plastic pollution in agricultural fields is the plastic mulch used by farmers to improve crop production. The plastic mulch is often not removed completely from the fields after harvest. Over time, the plastic mulch that is left of the fields is broken down into smaller particles which are dispersed by the wind or runoff. In the Region of Murcia in Spain, plastic mulch is heavily used for intensive vegetable farming. After harvest, sheep are released into the fields to graze on the vegetable residues. The objective of the study was to assess the plastic contamination in agricultural soil in Spain and the ingestion of plastic by sheep. Therefore, three research questions were established: i) What is the plastic content in agricultural soils where plastic mulch is commonly used? ii) Do livestock ingest the microplastics found in the soil? iii) How much plastic could be transported by the livestock? To answer these questions, we sampled top soils (0-10 cm) from 6 vegetable fields and collected sheep faeces from 5 different herds. The microplastic content was measured using density separation and visual identification. We found ~2 × 103 particles∙kg-1 in the soil and ~103 particles∙kg-1 in the faeces. The data show that plastic particles were present in the soil and that livestock ingested them. After ingesting plastic from one field, the sheep can become a source of microplastic contamination as they graze on other farms or grasslands. The potential transport of microplastics due to a herd of 1000 sheep was estimated to be ~106 particles∙ha-1∙y-1. Further studies should focus on: assessing how much of the plastic found in faeces comes directly from plastic mulching, estimating the plastic degradation in the guts of sheep and understanding the potential effects of these plastic residues on the health of livestock.
Collapse
Affiliation(s)
- Nicolas Beriot
- Soil Physics and Land Management Group, Wageningen University & Research, P.O. Box 47, 6700AA Wageningen, the Netherlands; Sustainable Use, Management and Reclamation of Soil and Water Research Group, Universidad Politécnica de Cartagena, Paseo Alfonso XIII, 48, 30203 Cartagena, Spain.
| | - Joost Peek
- Soil Physics and Land Management Group, Wageningen University & Research, P.O. Box 47, 6700AA Wageningen, the Netherlands
| | - Raul Zornoza
- Sustainable Use, Management and Reclamation of Soil and Water Research Group, Universidad Politécnica de Cartagena, Paseo Alfonso XIII, 48, 30203 Cartagena, Spain
| | - Violette Geissen
- Soil Physics and Land Management Group, Wageningen University & Research, P.O. Box 47, 6700AA Wageningen, the Netherlands
| | - Esperanza Huerta Lwanga
- Soil Physics and Land Management Group, Wageningen University & Research, P.O. Box 47, 6700AA Wageningen, the Netherlands; Agroecología, El Colegio de la Frontera Sur, Unidad Campeche, Campeche, Mexico
| |
Collapse
|
19
|
Affiliation(s)
- Kira L. Rahn
- Department of Chemistry, Iowa State University, 1605 Gilman Hall, 2415 Osborn Drive, Ames, Iowa 50011-1021, United States
| | - Robbyn K. Anand
- Department of Chemistry, Iowa State University, 1605 Gilman Hall, 2415 Osborn Drive, Ames, Iowa 50011-1021, United States
| |
Collapse
|
20
|
Thompson JR, Davies CD, Clausmeyer J, Crooks RM. Cation‐Specific Electrokinetic Separations Using Prussian Blue Intercalation Reactions. ChemElectroChem 2020. [DOI: 10.1002/celc.202001095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Jonathan R. Thompson
- Department of Chemistry and Texas Materials Institute The University of Texas at Austin 105 E. 24th St., Stop A5300 Austin, Texas 78712-1224 United States
| | - Collin D. Davies
- Department of Chemistry and Texas Materials Institute The University of Texas at Austin 105 E. 24th St., Stop A5300 Austin, Texas 78712-1224 United States
| | - Jan Clausmeyer
- Department of Chemistry and Texas Materials Institute The University of Texas at Austin 105 E. 24th St., Stop A5300 Austin, Texas 78712-1224 United States
| | - Richard M. Crooks
- Department of Chemistry and Texas Materials Institute The University of Texas at Austin 105 E. 24th St., Stop A5300 Austin, Texas 78712-1224 United States
| |
Collapse
|
21
|
Rius-Ayra O, Bouhnouf-Riahi O, LLorca-Isern N. Superhydrophobic and Sustainable Nanostructured Powdered Iron for the Efficient Separation of Oil-in-Water Emulsions and the Capture of Microplastics. ACS APPLIED MATERIALS & INTERFACES 2020; 12:45629-45640. [PMID: 32926613 DOI: 10.1021/acsami.0c13876] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The pollution of oceans and seas by oils and microplastics is a significant global issue affecting the economy and environment. Therefore, it is necessary to search for different technologies that can remove these pollutants in a sustainable way. Herein, superhydrophobic powdered iron was used to efficiently separate stabilized oil-in-water emulsions and, remarkably, capture microplastic fibers. High-energy ball milling of iron particles was applied to decrease particle size, increase the specific surface area, and produce a nanostructured material. This was combined with the liquid phase deposition of lauric acid to modify the surface free energy. The nanostructured powder showed superhydrophobicity (WCA = 154°) and superoleophilicity (OCA = 0°), which were fundamental in separating stabilized oil-in-water emulsions of hexane with an efficiency close to 100%. Because of the superhydrophobic/superoleophilic properties of the powdered iron and its intrinsic properties of being able to freely move and adapt to the different morphologies of microplastics under continuous stirring, this material can capture microplastic fibers. Thus, we present a novel dual application of a superhydrophobic material, which includes the capture of microplastics. This has not been reported previously and provides a new scope for future environmental sustainability.
Collapse
Affiliation(s)
- O Rius-Ayra
- CPCM Departament de Ciència dels Materials i Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - O Bouhnouf-Riahi
- CPCM Departament de Ciència dels Materials i Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - N LLorca-Isern
- CPCM Departament de Ciència dels Materials i Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| |
Collapse
|
22
|
Tutorial review: Enrichment and separation of neutral and charged species by ion concentration polarization focusing. Anal Chim Acta 2020; 1128:149-173. [PMID: 32825899 DOI: 10.1016/j.aca.2020.06.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 06/06/2020] [Accepted: 06/08/2020] [Indexed: 01/06/2023]
Abstract
Ion concentration polarization focusing (ICPF) is an electrokinetic technique, in which analytes are enriched and separated along a localized electric field gradient in the presence of a counter flow. This field gradient is generated by depletion of ions of the background electrolyte at an ion permselective junction. In this tutorial review, we summarize the fundamental principles and experimental parameters that govern selective ion transport and the stability of the enriched analyte plug. We also examine faradaic ICP (fICP), in which local ion concentration is modulated via electrochemical reactions as an attractive alternative to ICP that achieves similar performance with a decrease in both power consumption and Joule heating. The tutorial covers important challenges to the broad application of ICPF including undesired pH gradients, low volumetric throughput, samples that induce biofouling or are highly conductive, and limited approaches to on- or off-chip analysis. Recent developments in the field that seek to address these challenges are reviewed along with new approaches to maximize enrichment, focus uncharged analytes, and achieve enrichment and separation in water-in-oil droplets. For new practitioners, we discuss practical aspects of ICPF, such as strategies for device design and fabrication and the relative advantages of several types of ion selective junctions and electrodes. Lastly, we summarize tips and tricks for tackling common experimental challenges in ICPF.
Collapse
|