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Warren CG, Dasgupta PK. Liquid phase detection in the miniature scale. Microfluidic and capillary scale measurement and separation systems. A tutorial review. Anal Chim Acta 2024; 1305:342507. [PMID: 38677834 DOI: 10.1016/j.aca.2024.342507] [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: 01/08/2024] [Revised: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 04/29/2024]
Abstract
Microfluidic and capillary devices are increasingly being used in analytical applications while their overall size keeps decreasing. Detection sensitivity for these microdevices gains more importance as device sizes and consequently, sample volumes, decrease. This paper reviews optical, electrochemical, electrical, and mass spectrometric detection methods that are applicable to capillary scale and microfluidic devices, with brief introduction to the principles in each case. Much of this is considered in the context of separations. We do consider theoretical aspects of separations by open tubular liquid chromatography, arguably the most potentially fertile area of separations that has been left fallow largely because of lack of scale-appropriate detection methods. We also examine the theoretical basis of zone electrophoretic separations. Optical detection methods discussed include UV/Vis absorbance, fluorescence, chemiluminescence and refractometry. Amperometry is essentially the only electrochemical detection method used in microsystems. Suppressed conductance and especially contactless conductivity (admittance) detection are in wide use for the detection of ionic analytes. Microfluidic devices, integrated to various mass spectrometers, including ESI-MS, APCI-MS, and MALDI-MS are discussed. We consider the advantages and disadvantages of each detection method and compare the best reported limits of detection in as uniform a format as the available information allows. While this review pays more attention to recent developments, our primary focus has been on the novelty and ingenuity of the approach, regardless of when it was first proposed, as long as it can be potentially relevant to miniature platforms.
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Affiliation(s)
- Cable G Warren
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, 76019-0065, United States
| | - Purnendu K Dasgupta
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, 76019-0065, United States.
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Huang W, He G. On-column capillary suppressor for open tubular ion chromatography. Anal Chim Acta 2024; 1297:342372. [PMID: 38438241 DOI: 10.1016/j.aca.2024.342372] [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: 11/27/2023] [Revised: 02/07/2024] [Accepted: 02/12/2024] [Indexed: 03/06/2024]
Abstract
BACKGROUND Suppressors with different dead volumes are required to match different suppressed ion chromatography systems. Especially for suppressed open tubular ion chromatography (SOTIC), the dead volume is a critical parameter. Both connection tubes between open tubular (OT) columns and suppressors and the dead volumes of the suppressors should be as short/small as possible to minimize peak dispersion. Suppressors with different dead volumes are required to match the various suppressed ion chromatography systems that operate at low flow rates 20-200 nL/min. RESULTS We describe three designs of on-column capillary suppressors for SOTIC: (A) on-column electrodialytic suppressor prepared by making small cracks on the cycloolefin polymer (COP) capillary at targeted locations, (B) on-column electrodialytic suppressor built on a polyether ether ketone (PEEK) capillary by removing the wall materials at target locations, (C) on-column chemical suppressor based on a single cut on a PEEK capillary at a targeted location a single cut on a PEEK capillary at a targeted location. The on-column electrodialytic suppressors work in two different modes with suppression voltage applied in co-current and counter-current direction to the eluent flow. Because of very narrow column inner diameter (i.d.), up to several hundred volts were required to suppress the hydroxide eluent, but it was found the there was a >90% loss of analytes in the suppressor accompanied with a high noise level after on-column electrodialytic suppression. Theoretical analysis reveals that high suppression voltage significantly affects the retention of specific analytes by electromigration. Further analysis indicated that the electrodialytic on-column suppressor in co-current mode would behave totally different from traditional suppressors. The on-column chemical suppression, with minimum dead volume of 0.27 nL, provides fairly well suppression of low hydroxide eluent without analyte loss in the suppressor. In design C, an efficiency of 47000 ± 1800 plates/m for Cl-, corresponding to a peak volume of 17.9 ± 0.7 nL, was obtained when separating five anion mixture (0.5 mM each) in the 25 μm i.d. AS18 latex coated PEEK OT column with an injection of 7.3 nL. Theoretical calculation revealed that a column efficiency loss of ≤3% would result in a cylindrical chemical suppression channel and thus it is taken as the acceptable dispersion contribution originating from the on-column chemical suppressor. SIGNIFICANCE Different on-column suppressors have been designed on OT columns with i.d.s less than 30 μm. Two electrodialytic on-column suppressor designs with eluent flow parallel to the direction of electric field were proposed and tested. The eluent flow rate, analytes' retention behavior, resistance of suppression channel, current-voltage relationship, and working principles in both co-current and counter-current were experimentally investigated and comprehensively discussed. It was found that although the on-column electrodialytic suppressions (Design A and B) are not feasible in practice, the electrodialytic on-column suppressor on co-current mode has a potential of being used as an enriching capillary column for analyte ions. Design C provides fairly well chemical suppression. Theoretical calculation indicates that the loss of column efficiency can be controlled within 3%.
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Affiliation(s)
- Weixiong Huang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430078, Hubei, China; Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019-0065, United States.
| | - Ge He
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430078, Hubei, China
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Huang W, Stamos BN. Portable light weight open tubular ion chromatograph for field determination of environmental anions. J Chromatogr A 2023; 1711:464464. [PMID: 37871504 DOI: 10.1016/j.chroma.2023.464464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 10/10/2023] [Accepted: 10/17/2023] [Indexed: 10/25/2023]
Abstract
We report a battery powered non-suppressed open tubular ion chromatograph (NSOTIC) that weighs less than 3 kg with on-board rechargeable lithium-ion batteries that provide power for 18 h of operation. It is contained in an aluminum case measuring 30 × 25 × 16 cm. Separation relies on open tubular (OT) chromatographic columns which eliminate the need for high pressure pumps, drastically reducing weight and complexity. Eluent consumption is less than 100 µL per separation. Eluent is supplied from a pressurized vessel via a voltage-controlled electronic pressure controller. Flow rates are typically <200 nL/min which allows a single 16-20 g gas cartridge to perform hundreds of separations. Two anions, chloride and nitrate, in Atacama soil samples were field determined by running the portable NSOTIC. More samples were lab analyzed by commercial IC and IC/MS-MS (only perchlorate due to its low concentration level). To demonstrate the feasibility of running NSOTIC on sample analysis, samples were tested by both non-portable and portable NSOTIC.
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Affiliation(s)
- Weixiong Huang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430078, Hubei, China; Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019-0065, United States.
| | - Brian N Stamos
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019-0065, United States
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Maleki F, Chouhan B, Shelor CP, Dasgupta PK. Moldable capillary suppressor for open tubular ion chromatography based on a polymeric ion exchanger. TALANTA OPEN 2021. [DOI: 10.1016/j.talo.2021.100062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Yang B, Li Z. [Advances of electrodialytic technologies used in ion chromatography]. Se Pu 2021; 39:130-133. [PMID: 34227345 PMCID: PMC9274837 DOI: 10.3724/sp.j.1123.2020.07016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
电渗析器件通常定义为在电场作用下操纵离子从一种溶液穿过离子交换膜迁移到另外一种溶液的一种设备。它可以通过电解水产生氢离子或氢氧根离子,从而用于离子色谱系统的淋洗液在线制备、抑制或检测。相较于人工配制淋洗液或再生液,电渗析技术具有绿色、高效、纯度高、自动化程度高等优势。因此基于电渗析器件的离子色谱系统应用范围越来越大。该文简要评述了近几年该器件的研究进展,具体包括电致淋洗液发生器、电致膜抑制器和电渗析样品前处理器。
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Affiliation(s)
- Bingcheng Yang
- School of Pharmacy, East-China University of Science and Technology, Shanghai 200237, China
| | - Zongying Li
- School of Pharmacy, East-China University of Science and Technology, Shanghai 200237, China
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Shelor CP, Yoshikawa K, Dasgupta PK. Automated Programmable Generation of Broad pH Range Volatile Ionic Eluents for Liquid Chromatography. Anal Chem 2021; 93:5442-5450. [PMID: 33759496 DOI: 10.1021/acs.analchem.0c05089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Many of the universal detectors in liquid chromatography, including mass spectrometry, must completely volatilize the chromatographic eluent first before further processing and detection of the analytes. A basic requirement is that the eluent does not contain a nonvolatile dissolved component. However, separation of biomolecules must be conducted in mostly aqueous media of compatible pH and ionic strength if their biological activity must survive the separation process. Combinations of ammonia with acetic and formic acids are commonly used as eluent for this purpose but generally maximum concentrations that can be tolerated are relatively low. Further, buffering is good only over a limited pH range. We describe a system where the eluent is generated in an automated pressure-programmed manner from high-purity gaseous NH3 and CO2 through gas-permeable membrane devices. This can be aided by the prior presence of formic/acetic acids in the mobile phase to extend the attainable low pH limit. We outline the fundamental pH, ionic strength, and buffer intensity considerations and demonstrate the application of such eluents in the separation of amino acids, proteins, and monoclonal antibodies. We also demonstrate the use of dissolved CO2 as an ion-pairing agent in the separation of chiral amines.
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Affiliation(s)
- Charles Phillip Shelor
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Kenji Yoshikawa
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Purnendu K Dasgupta
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019-0065, United States
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Davis JJ, Foster SW, Grinias JP. Low-cost and open-source strategies for chemical separations. J Chromatogr A 2021; 1638:461820. [PMID: 33453654 PMCID: PMC7870555 DOI: 10.1016/j.chroma.2020.461820] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/12/2020] [Accepted: 12/14/2020] [Indexed: 12/18/2022]
Abstract
In recent years, a trend toward utilizing open access resources for laboratory research has begun. Open-source design strategies for scientific hardware rely upon the use of widely available parts, especially those that can be directly printed using additive manufacturing techniques and electronic components that can be connected to low-cost microcontrollers. Open-source software eliminates the need for expensive commercial licenses and provides the opportunity to design programs for specific needs. In this review, the impact of the "open-source movement" within the field of chemical separations is described, primarily through a comprehensive look at research in this area over the past five years. Topics that are covered include general laboratory equipment, sample preparation techniques, separations-based analysis, detection strategies, electronic system control, and software for data processing. Remaining hurdles and possible opportunities for further adoption of open-source approaches in the context of these separations-related topics are also discussed.
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Affiliation(s)
- Joshua J Davis
- Department of Chemistry & Biochemistry, Rowan University, Glassboro, NJ 08028, United States
| | - Samuel W Foster
- Department of Chemistry & Biochemistry, Rowan University, Glassboro, NJ 08028, United States
| | - James P Grinias
- Department of Chemistry & Biochemistry, Rowan University, Glassboro, NJ 08028, United States.
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Huang W. Open tubular ion chromatography: A state-of-the-Art review. Anal Chim Acta 2021; 1143:210-224. [PMID: 33384120 DOI: 10.1016/j.aca.2020.08.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 08/04/2020] [Accepted: 08/06/2020] [Indexed: 11/19/2022]
Abstract
This review summarizes the progress in open tubular ion chromatography (OTIC) over the period from 1981 to 2020. Although OTIC columns provide superior column efficiency, require very little sample volumes, and consume a minimum level of eluents compared to regular packed columns, not many reports can be found from the literature mainly due to the difficulties in the preparation of OTIC columns and the harsh system requirements, such as pL-nL injections and extremely small detection volumes. However, technical advances, e.g., capacitively coupled contactless conductivity detectors (C4Ds), hydroxide eluent compatible polymer-based OTIC columns, electrodialytic capillary suppressors, and nanovolume gas-free hydroxide eluent generators (EGs), have removed the obstacles to OTIC. As such, in this review, the author focused on the development of the key components in an OTIC system from the perspective of instrument development. A brief revisit of open tubular (OT) column theory is first presented, followed by a discussion of the system configuration and component development. Attention is given to the advances in the development of the suppressed open tubular ion chromatography (SOTIC) system.
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Affiliation(s)
- Weixiong Huang
- School of Environmental Studies, China University of Geosciences, Wuhan, 430078, Hubei, China.
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Liu S, Pan Z, Liang Y, Li F, Breadmore MC, Zhang M. An electrophoretic ion analyzer for on-site autonomous water monitoring. J Chromatogr A 2020; 1637:461791. [PMID: 33359795 DOI: 10.1016/j.chroma.2020.461791] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/11/2020] [Accepted: 12/04/2020] [Indexed: 01/05/2023]
Abstract
An on-site ion analyzer based on capillary electrophoresis with pressure-driven flow through injection and capacitively coupled contactless conductivity detection has been developed for field monitoring of cations and anions in environmental waters. Automated time-pressure based hydrodynamic injection provides stable pL-nL scale injection (RSD = 1.96%, n = 30). A mixture of 400 mM Bis-Tris, 400 mM MOPS and 2 mM 18-crown-6 is used as the background electrolyte to provide repeatable separations. A proprietary hydrophilic coated 25 μm id capillary is used to suppress the electroosmotic flow. Separations of anions (Cl-, NO3-, NO2-, SO42-, F- and PO43-) and cations (NH4+, K+, Na+, Ca2+ and Mg2+) are achieved by switching the polarity of the high voltage power supply in two individual runs. Signal fluctuations caused by the temperature or viscosity changes in on-site monitoring are corrected by on-line introduction of internal standards. RSDs of the migration time and the corrected peak height over ~35 h and 350 analysis cycles are <4.06%. The LODs of inorganic ions are in the range of 2.1 μM (K+) to 6.8 μM (PO43-). The feasibility for on-site water monitoring with this system has been validated by a standard Ion chromatography method with comparable results obtained.
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Affiliation(s)
- Shuai Liu
- School of Life and Environmental Sciences, Guangxi Key Laboratory of Automatic Detecting Technology and Instruments, Guilin University of Electronic Technology, Guilin, Guangxi, 541004, China
| | - Zhen Pan
- School of Life and Environmental Sciences, Guangxi Key Laboratory of Automatic Detecting Technology and Instruments, Guilin University of Electronic Technology, Guilin, Guangxi, 541004, China
| | - Ying Liang
- School of Life and Environmental Sciences, Guangxi Key Laboratory of Automatic Detecting Technology and Instruments, Guilin University of Electronic Technology, Guilin, Guangxi, 541004, China.
| | - Feng Li
- Australian Centre for Research on Separation Science, School of Natural Sciences-Chemistry, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Michael C Breadmore
- Australian Centre for Research on Separation Science, School of Natural Sciences-Chemistry, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Min Zhang
- School of Life and Environmental Sciences, Guangxi Key Laboratory of Automatic Detecting Technology and Instruments, Guilin University of Electronic Technology, Guilin, Guangxi, 541004, China.
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Sugo Y, Miyachi R, Maruyama YH, Ohira SI, Mori M, Ishioka NS, Toda K. Electrodialytic Handling of Radioactive Metal Ions for Preparation of Tracer Reagents. Anal Chem 2020; 92:14953-14958. [PMID: 32959650 DOI: 10.1021/acs.analchem.0c02456] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Radioactive metals are applied in biochemistry, medical diagnosis such as positron emission tomography (PET), and cancer therapy. However, the activity of radioisotopes exponentially decreases with time; therefore, rapid and reliable probe preparation methods are strongly recommended. In the present study, electrodialytic radioactive metal ion handling is studied for counter ion conversion and in-line probe synthesis. Presently, counter ion conversion and probe synthesis are achieved by evaporative dryness and solution mixing, respectively. Evaporative dryness is time-consuming and is a possible process that can lead to loss of radioactive metal ions. Mixing of solutions for synthesis makes dilution and undesirable effects of counter ion on the synthesis. An optimized electrodialytic flow device can transfer a radioisotope, 64Cu2+, with high recovery from HCl matrices to HNO3 (∼100%). Matrices can also be transferred into acetic acid and citric acid, even though the concentration of the metal ion is at the picomolar level. The ion transfer can also be achieved with simultaneous counter ion conversion, complex synthesis, and enrichment. When the ligand was dissolved in an acceptor solution, the transferred metal ions from the donor were well mixed and formed a complex with the ligand in-line. The efficiency of the synthesis was ∼100% for 1.0 pM 64Cu. A relatively larger donor-to-acceptor flow rate can enrich the metal ion in the acceptor solution continuously. The flow rate ratio of 10 (donor/acceptor) can achieve 10 times enrichment. The present electrodialytic ion handling method can treat ultra-trace radioisotopes in a closed system. With this method, rapid, effective, and safe radioisotope treatments were achieved.
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Affiliation(s)
- Yumi Sugo
- Department of Radiation-Applied Biology Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki, Takasaki 370-1292, Japan
| | - Ryoma Miyachi
- Department of Chemistry, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
| | - Yo-Hei Maruyama
- Faculty of Science and Technology, Kochi University, 2-5-1, Akebono-cho, Kochi 780-8520, Japan
| | - Shin-Ichi Ohira
- Department of Chemistry, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
| | - Masanobu Mori
- Faculty of Science and Technology, Kochi University, 2-5-1, Akebono-cho, Kochi 780-8520, Japan
| | - Noriko S Ishioka
- Department of Radiation-Applied Biology Research, Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki, Takasaki 370-1292, Japan
| | - Kei Toda
- Department of Chemistry, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
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Maleki F, Dasgupta PK. Moldable Strong Cation Exchange Polymer and Microchannel Fabrication. Anal Chem 2020; 92:13378-13386. [DOI: 10.1021/acs.analchem.0c02754] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fereshteh Maleki
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Purnendu K. Dasgupta
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019-0065, United States
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