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Silva-Neto HA, Duarte-Junior GF, Rocha DS, Bedioui F, Varenne A, Coltro WKT. Recycling 3D Printed Residues for the Development of Disposable Paper-Based Electrochemical Sensors. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 36884339 DOI: 10.1021/acsami.3c00370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Here, we propose a recyclable approach using acrylonitrile-butadiene-styrene (ABS) residues from additive manufacturing in combination with low-cost and accessible graphite flakes as a novel and potential mixture for creating a conductive paste. The graphite particles were successfully incorporated in the recycled thermoplastic composite when solubilized with acetone and the mixture demonstrated greater adherence to different substrates, among which cellulose-based material made possible the construction of a paper-based electrochemical sensor (PES). The morphological, structural, and electrochemical characterizations of the recycled electrode material were demonstrated to be similar to those of the traditional carbon-based surfaces. Faradaic responses based on redox probe activity ([Fe(CN)6]3-/4-) exhibited well-defined peak currents and diffusional mass transfer as a quasi-reversible system (96 ± 5 mV) with a fast heterogeneous rate constant value of 2 × 10-3 cm s-1. To improve the electrode electrochemical properties, both the PES and the classical 3D-printed electrode surfaces were modified with a combination of multiwalled carbon nanotubes (MWCNTs), graphene oxide (GO), and copper. Both electrode surfaces demonstrated the suitable oxidation of nitrite at 0.6 and 0.5 V vs Ag, respectively. The calculated analytical sensitivities for PES and 3D-printed electrodes were 0.005 and 0.002 μA/(μmol L-1), respectively. The proposed PES was applied for the indirect amperometric analysis of S-nitroso-cysteine (CysNO) in serum samples via nitrite quantitation, demonstrating a limit of detection of 4.1 μmol L-1, with statistically similar values when compared to quantitative analysis of the same samples by spectrophotometry (paired t test, 95% confidence limit). The evaluated electroanalytical approach exhibited linear behavior for nitrite in the concentration range between 10 and 125 μmol L-1, which is suitable for realizing clinical diagnosis involving Parkinson's disease, for example. This proof of concept shows the great promise of this recyclable strategy combining ABS residues and conductive particles in the context of green chemical protocols for constructing disposable sensors.
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Affiliation(s)
- Habdias A Silva-Neto
- Instituto de Química, Universidade Federal de Goiás, 74690-900, Goiânia, GO Brazil
| | | | - Danielly S Rocha
- Instituto de Química, Universidade Federal de Goiás, 74690-900, Goiânia, GO Brazil
| | - Fethi Bedioui
- Institute of Chemistry for Life and Health Sciences i-CLeHS, Chimie ParisTech-PSL/CNRS, Paris 8060, France
| | - Anne Varenne
- Institute of Chemistry for Life and Health Sciences i-CLeHS, Chimie ParisTech-PSL/CNRS, Paris 8060, France
| | - Wendell K T Coltro
- Instituto de Química, Universidade Federal de Goiás, 74690-900, Goiânia, GO Brazil
- Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas 13084-971, São Paulo Brazil
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2
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Gross E, Lowry E, Schaffer L, Henry C. Electrogenerated Chemiluminescent Detection of Polyamines on a Microfluidic Device Using Micromolded Carbon Paste Microelectrodes. ELECTROANAL 2022. [DOI: 10.1002/elan.202100410] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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3
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Romano MP, Lionetto MG, Mangone A, De Bartolomeo AR, Giordano ME, Contini D, Guascito MR. Development and characterization of a gold nanoparticles glassy carbon modified electrode for dithiotreitol (DTT) detection suitable to be applied for determination of atmospheric particulate oxidative potential. Anal Chim Acta 2022; 1206:339556. [DOI: 10.1016/j.aca.2022.339556] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 01/20/2022] [Accepted: 01/24/2022] [Indexed: 11/01/2022]
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4
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Koczorowski T, Cerbin-Koczorowska M, Rębiś T. Azaporphyrins Embedded on Carbon-Based Nanomaterials for Potential Use in Electrochemical Sensing-A Review. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2861. [PMID: 34835626 PMCID: PMC8620011 DOI: 10.3390/nano11112861] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/24/2021] [Accepted: 10/25/2021] [Indexed: 01/15/2023]
Abstract
Phthalocyanines and porphyrazines as macrocyclic aza-analogues of well-known porphyrins were deposited on diverse carbon-based nanomaterials and investigated as sensing devices. The extended π-conjugated electron system of these macrocycles influences their ability to create stable hybrid systems with graphene or carbon nanotubes commonly based on π-π stacking interactions. During a 15-year period, the electrodes modified by deposition of these systems have been applied for the determination of diverse analytes, such as food pollutants, heavy metals, catecholamines, thiols, glucose, peroxides, some active pharmaceutical ingredients, and poisonous gases. These procedures have also taken place, on occasion, in the presence of various polymers, ionic liquids, and other moieties. In the review, studies are presented that were performed for sensing purposes, involving azaporphyrins embedded on graphene, graphene oxide or carbon nanotubes (both single and multi-walled ones). Moreover, possible methods of electrode fabrication, limits of detection of each analyte, as well as examples of macrocyclic compounds applied as sensing materials, are critically discussed.
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Affiliation(s)
- Tomasz Koczorowski
- Chair and Department of Chemical Technology of Drugs, Poznan University of Medical Sciences, Grunwaldzka 6, 60-780 Poznan, Poland
| | - Magdalena Cerbin-Koczorowska
- Department of Medical Education, Poznan University of Medical Sciences, 7 Rokietnicka Str., 60-806 Poznan, Poland;
| | - Tomasz Rębiś
- Institute of Chemistry and Technical Electrochemistry, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland;
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5
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Leroy A, Teixidor J, Bertsch A, Renaud P. In-flow electrochemical detection of chemicals in droplets with pyrolysed photoresist electrodes: application as a module for quantification of microsampled dopamine. LAB ON A CHIP 2021; 21:3328-3337. [PMID: 34250532 DOI: 10.1039/d1lc00116g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The electrochemical quantification of analytes in droplets of PBS separated by a fluorinated phase was investigated. PDMS-fused silica chips with pyrolysed photoresist electrodes were prepared using a simple fabrication technique and used to analyze droplets in flow. Potentiostatic chronoamperometry provided current readouts consistent with mass transport and the concentration inside the droplets. This paper highlights measurements of dopamine in droplets in T-junction microfluidic chips at unprecedently low concentrations, with a limit of detection of 207 nM and a linear range of 0.21-20 μM, giving results similar to continuous flow electrochemistry and allowing the analysis in the striatal extracellular range (<1 μM). The system was applied to the quick and reliable on-line detection of dopamine concentration steps in droplets collected with a microsampling probe in vitro, demonstrating the usefulness of the electrochemical device as a quantification module for microsampled chemicals in droplets.
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Affiliation(s)
- Albert Leroy
- EPFL-STI-IMT-LMIS4, École Polytechnique Fédérale de Lausanne, Station 17, CH-1015 Lausanne, Switzerland.
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6
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Gholizadeh H, Ong HX, Bradbury P, Kourmatzis A, Traini D, Young P, Li M, Cheng S. Real-time quantitative monitoring of in vitro nasal drug delivery by a nasal epithelial mucosa-on-a-chip model. Expert Opin Drug Deliv 2021; 18:803-818. [PMID: 33410717 DOI: 10.1080/17425247.2021.1873274] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OBJECTIVES A human nasal epithelial mucosa (NEM) on-a-chip is developed integrated with a novel carbon nanofibers-modified carbon electrode for real-time quantitative monitoring of in vitro nasal drug delivery. The integration of platinum electrodes in the chip also enables real-time measurement of transepithelial electrical resistance (TEER). METHODS The air-liquid interface culture of nasal epithelial RPMI 2650 cells in the NEM-on-a-chip was optimized to mimic the key functional characteristics of the human nasal mucosa. The epithelial transport of ibuprofen in the NEM-on-a-chip was electrochemically monitored in real-time under static and physiologically realistic dynamic flow conditions. RESULTS The NEM-on-a-chip mimics the mucus production and nasal epithelial barrier function of the human nasal mucosa. The real-time drug quantification by the NEM-on-a-chip was validated versus the high-performance liquid chromatography method. The drug transport rate monitored in the NEM-on-a-chip was influenced by the flow in the bottom compartment of the chip, highlighting the importance of emulating the dynamic in vivo condition for nasal drug transport studies. CONCLUSION This novel NEM-on-a-chip can be a low-cost and time-efficient alternative to the costly laborious conventional techniques for in vitro nasal drug transport assays. Importantly, its dynamic microenvironment enables conducting nasal drug transport tests under physiologically relevant dynamic conditions.
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Affiliation(s)
- Hanieh Gholizadeh
- School of Engineering, Macquarie University, Sydney, NSW, Australia.,Respiratory Technology, Woolcock Institute of Medical Research, Glebe, NSW, Australia
| | - Hui Xin Ong
- Respiratory Technology, Woolcock Institute of Medical Research, Glebe, NSW, Australia.,Discipline of Pharmacology, Medicine and Health, University of Sydney, Camperdown, NSW, Australia
| | - Peta Bradbury
- Respiratory Technology, Woolcock Institute of Medical Research, Glebe, NSW, Australia
| | - Agisilaos Kourmatzis
- School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Camperdown, NSW, Australia
| | - Daniela Traini
- Respiratory Technology, Woolcock Institute of Medical Research, Glebe, NSW, Australia.,Discipline of Pharmacology, Medicine and Health, University of Sydney, Camperdown, NSW, Australia
| | - Paul Young
- Respiratory Technology, Woolcock Institute of Medical Research, Glebe, NSW, Australia.,Discipline of Pharmacology, Medicine and Health, University of Sydney, Camperdown, NSW, Australia
| | - Ming Li
- School of Engineering, Macquarie University, Sydney, NSW, Australia
| | - Shaokoon Cheng
- School of Engineering, Macquarie University, Sydney, NSW, Australia
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7
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Silva-Neto HA, Cardoso TMG, McMahon CJ, Sgobbi LF, Henry CS, Coltro WKT. Plug-and-play assembly of paper-based colorimetric and electrochemical devices for multiplexed detection of metals. Analyst 2021; 146:3463-3473. [DOI: 10.1039/d1an00176k] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We propose a “plug-and-play” (PnP) assembly for coupling paper-based colorimetric and electrochemical devices for multiplexed detection of metals.
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Affiliation(s)
| | | | | | - Lívia F. Sgobbi
- Instituto de Química
- Universidade Federal de Goiás
- Goiânia
- Brazil
| | | | - Wendell K. T. Coltro
- Instituto de Química
- Universidade Federal de Goiás
- Goiânia
- Brazil
- Instituto Nacional de Ciência e Tecnologia de Bioanalítica
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8
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Yazdian Kashani S, Afzalian A, Shirinichi F, Keshavarz Moraveji M. Microfluidics for core-shell drug carrier particles - a review. RSC Adv 2020; 11:229-249. [PMID: 35423057 PMCID: PMC8691093 DOI: 10.1039/d0ra08607j] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/07/2020] [Indexed: 01/07/2023] Open
Abstract
Core-shell drug-carrier particles are known for their unique features. Due to the combination of superior properties not exhibited by the individual components, core-shell particles have gained a lot of interest. The structures could integrate core and shell characteristics and properties. These particles were designed for controlled drug release in the desired location. Therefore, the side effects would be minimized. So, these particles' advantages have led to the introduction of new methods and ideas for their fabrication. In the past few years, the generation of drug carrier core-shell particles in microfluidic chips has attracted much attention. This method makes it possible to produce particles at nanometer and micrometer levels of the same shape and size; it usually costs less than other methods. The other advantages of using microfluidic techniques compared to conventional bulk methods are integration capability, reproducibility, and higher efficiency. These advantages have created a positive outlook on this approach. This review gives an overview of the various fluidic concepts that are used to generate microparticles or nanoparticles. Also, an overview of traditional and more recent microfluidic devices and their design and structure for the generation of core-shell particles is given. The unique benefits of the microfluidic technique for core-shell drug carrier particle generation are demonstrated.
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Affiliation(s)
- Sepideh Yazdian Kashani
- Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic) 1591634311 Tehran Iran +98 21 64543182
| | - Amir Afzalian
- Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic) 1591634311 Tehran Iran +98 21 64543182
| | - Farbod Shirinichi
- Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic) 1591634311 Tehran Iran +98 21 64543182
| | - Mostafa Keshavarz Moraveji
- Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic) 1591634311 Tehran Iran +98 21 64543182
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9
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Arvinte A, Sesay AM, Virtanen V. Designing carbon reinforced PMMA composites for integrated electrodes as electrochemical detectors in PMMA microchips. J Electroanal Chem (Lausanne) 2020. [DOI: 10.1016/j.jelechem.2020.114486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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Gross EM, Porter LR, Stark NR, Lowry ER, Schaffer LV, Maddipati SS, Hoyt DJ, Stombaugh SE, Peila SR, Henry CS. Micromolded Carbon Paste Microelectrodes for Electrogenerated Chemiluminescent Detection on Microfluidic Devices. ChemElectroChem 2020; 7:3244-3252. [DOI: 10.1002/celc.202000366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Erin M. Gross
- Department of ChemistryCreighton University 2500 California Plaza Omaha NE 68178 USA
| | - Laura R. Porter
- Department of ChemistryCreighton University 2500 California Plaza Omaha NE 68178 USA
| | - Nicholas R. Stark
- Department of ChemistryCreighton University 2500 California Plaza Omaha NE 68178 USA
| | - Emily R. Lowry
- Department of ChemistryCreighton University 2500 California Plaza Omaha NE 68178 USA
| | - Leah V. Schaffer
- Department of ChemistryCreighton University 2500 California Plaza Omaha NE 68178 USA
| | - Sai Sujana Maddipati
- Department of ChemistryCreighton University 2500 California Plaza Omaha NE 68178 USA
| | - Dylan J. Hoyt
- Department of ChemistryCreighton University 2500 California Plaza Omaha NE 68178 USA
| | - Sarah E. Stombaugh
- Department of ChemistryCreighton University 2500 California Plaza Omaha NE 68178 USA
| | - Sarah R. Peila
- Department of ChemistryCreighton University 2500 California Plaza Omaha NE 68178 USA
| | - Charles S. Henry
- Department of ChemistryColorado State University Fort Collins CO 80523 USA
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11
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Gouyon J, d’Orlyé F, Griveau S, Bedioui F, Varenne A. Characterization of home-made graphite/PDMS microband electrodes for amperometric detection in an original reusable glass-NOA®-PDMS electrophoretic microdevice. Electrochim Acta 2020. [DOI: 10.1016/j.electacta.2019.135164] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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12
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Nishiyama K, Hoshikawa K, Maeki M, Ishida A, Tani H, Tokeshi M. A Concentric Ring Electrode for a Wall‐jet Cell in a Microfluidic Device. ELECTROANAL 2019. [DOI: 10.1002/elan.201900109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Keine Nishiyama
- Graduate School of Chemical Sciences and EngineeringHokkaido University, Kita 13 Nishi 8, Kita-ku Sapporo 060-8628 Japan
| | - Koki Hoshikawa
- Graduate School of Chemical Sciences and EngineeringHokkaido University, Kita 13 Nishi 8, Kita-ku Sapporo 060-8628 Japan
| | - Masatoshi Maeki
- Division of Applied Chemistry, Faculty of EngineeringHokkaido University, Kita 13 Nishi 8, Kita-ku Sapporo 060-8628 Japan
| | - Akihiko Ishida
- Division of Applied Chemistry, Faculty of EngineeringHokkaido University, Kita 13 Nishi 8, Kita-ku Sapporo 060-8628 Japan
| | - Hirofumi Tani
- Division of Applied Chemistry, Faculty of EngineeringHokkaido University, Kita 13 Nishi 8, Kita-ku Sapporo 060-8628 Japan
| | - Manabu Tokeshi
- Division of Applied Chemistry, Faculty of EngineeringHokkaido University, Kita 13 Nishi 8, Kita-ku Sapporo 060-8628 Japan
- ImPACT Research Center for Advanced NanobiodevicesNagoya University, Furo-cho, Chikusa-ku Nagoya 464-8603 Japan
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13
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Klunder KJ, Clark KM, McCord C, Berg KE, Minteer SD, Henry CS. Polycaprolactone-enabled sealing and carbon composite electrode integration into electrochemical microfluidics. LAB ON A CHIP 2019; 19:2589-2597. [PMID: 31250868 PMCID: PMC6801002 DOI: 10.1039/c9lc00417c] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Combining electrochemistry with microfluidics is attractive for a wide array of applications including multiplexing, automation, and high-throughput screening. Electrochemical instrumentation also has the advantage of being low-cost and can enable high analyte sensitivity. For many electrochemical microfluidic applications, carbon electrodes are more desirable than noble metals because they are resistant to fouling, have high activity, and large electrochemical solvent windows. At present, fabrication of electrochemical microfluidic devices bearing integrated carbon electrodes remains a challenge. Here, a new system for integrating polycaprolactone (PCL) and carbon composite electrodes into microfluidics is presented. The PCL : carbon composites have excellent electrochemical activity towards a wide range of analytes as well as high electrical conductivity (∼1000 S m-1). The new system utilizes a laser cutter for fast, simple fabrication of microfluidics using PCL as a bonding layer. As a proof-of-concept application, oil-in-water and water-in-oil droplets are electrochemically analysed. Small-scale electrochemical organic synthesis for TEMPO mediated alcohol oxidation is also demonstrated.
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Affiliation(s)
- Kevin J Klunder
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA. and Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Kaylee M Clark
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
| | - Cynthia McCord
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
| | - Kathleen E Berg
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
| | - Shelley D Minteer
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Charles S Henry
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
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14
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Berg KE, Turner LR, Benka-Coker ML, Rajkumar S, Young BN, Peel JL, Clark ML, Volckens J, Henry CS. Electrochemical Dithiothreitol Assay for Large-Scale Particulate Matter Studies. AEROSOL SCIENCE AND TECHNOLOGY : THE JOURNAL OF THE AMERICAN ASSOCIATION FOR AEROSOL RESEARCH 2019; 53:268-275. [PMID: 31588161 PMCID: PMC6777574 DOI: 10.1080/02786826.2018.1560391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 11/11/2018] [Accepted: 11/25/2018] [Indexed: 06/10/2023]
Abstract
Particulate matter (PM) air pollution is associated with human morbidity and mortality. Measuring PM oxidative potential has been shown to provide a predictive measurement between PM exposure and adverse health impacts. The dithiothreitol (DTT) assay is commonly used to measure the oxidative potential of PM2.5 (PM less than 2.5 μm aerodynamic diameter). In the common, kinetic form of this assay, the decay of DTT is quantified over time (indirectly) using 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB, Ellman's reagent) via UV/vis absorbance spectroscopy. The loss of DTT can also be quantified directly using electrochemical detection. The objectives of this work were (1) to evaluate the electrochemical assay, using commercially available equipment, relative to the UV/vis absorbance assay, and (2) to apply the electrochemical method to a large (>100) number of PM2.5 aerosol filter samples. Also presented here is the comparison an end-point assay to the kinetic assay, in an attempt to reduce the time, labor, and materials neccssary to quantify PM oxidative potential. The end-point, electrochemical assay gave comparable results to the UV/vis absorbance assay for PM filter sample analysis. Finally, high filter mass loadings (higher than about 0.5 μg PM per mm2 filter) lead to sub-optimal DTT assay performance, which suggests future studies should limit particle mass loadings on filters.
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Affiliation(s)
| | | | - Megan L. Benka-Coker
- Dept of Environmental and Radiological Health Sciences, Colorado State University
| | - Sarah Rajkumar
- Dept of Environmental and Radiological Health Sciences, Colorado State University
| | - Bonnie N. Young
- Dept of Environmental and Radiological Health Sciences, Colorado State University
| | - Jennifer L. Peel
- Dept of Environmental and Radiological Health Sciences, Colorado State University
| | - Maggie L. Clark
- Dept of Environmental and Radiological Health Sciences, Colorado State University
| | - John Volckens
- Dept of Environmental and Radiological Health Sciences, Colorado State University
- Dept of Mechanical Engineering, Colorado State University
| | - Charles S. Henry
- Dept of Chemistry, Colorado State University
- Dept of Chemical & Biological Engineering, Colorado State University
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15
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Lynch KB, Chen A, Liu S. Miniaturized high-performance liquid chromatography instrumentation. Talanta 2017; 177:94-103. [PMID: 29108588 DOI: 10.1016/j.talanta.2017.09.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/04/2017] [Accepted: 09/06/2017] [Indexed: 12/26/2022]
Abstract
Miniaturized high performance liquid chromatography (HPLC) has attracted increasing attention for its potential in high-throughput analyses and point-of-care applications. In this review we highlight the recent advancements in HPLC system miniaturization. We focus on the major components that constitute these instruments along with their respective advantages and drawbacks as well as present a few representative miniaturized HPLC systems. We discuss briefly some of the applications and also anticipate the future development trends of these instrumental platforms.
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Affiliation(s)
- Kyle B Lynch
- Department of Chemistry and Biochemistry, University of Oklahoma, USA.
| | - Apeng Chen
- Department of Chemistry and Biochemistry, University of Oklahoma, USA
| | - Shaorong Liu
- Department of Chemistry and Biochemistry, University of Oklahoma, USA
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16
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A sensitive and selective on-line amperometric sulfite biosensor using sulfite oxidase immobilized on a magnetite-gold-folate nanocomposite modified carbon-paste electrode. Talanta 2016; 156-157:154-162. [DOI: 10.1016/j.talanta.2016.04.066] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 04/27/2016] [Accepted: 04/28/2016] [Indexed: 01/06/2023]
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17
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Reid RC, Jones SR, Hickey DP, Minteer SD, Gale BK. Modeling Carbon Nanotube Connectivity and Surface Activity in a Contact Lens Biofuel Cell. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.04.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Rattanarat P, Suea-Ngam A, Ruecha N, Siangproh W, Henry CS, Srisa-Art M, Chailapakul O. Graphene-polyaniline modified electrochemical droplet-based microfluidic sensor for high-throughput determination of 4-aminophenol. Anal Chim Acta 2016; 925:51-60. [PMID: 27188317 DOI: 10.1016/j.aca.2016.03.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/29/2015] [Accepted: 03/07/2016] [Indexed: 01/12/2023]
Abstract
We report herein the first development of graphene-polyaniline modified carbon paste electrode (G-PANI/CPE) coupled with droplet-based microfluidic sensor for high-throughput detection of 4-aminophenol (4-AP) in pharmaceutical paracetamol (PA) formulations. A simple T-junction microfluidic platform using an oil flow rate of 1.8 μL/min and an aqueous flow rate of 0.8 μL/min was used to produce aqueous testing microdroplets continuously. The microchannel was designed to extend the aqueous droplet to cover all 3 electrodes, allowing for electrochemical measurements in a single droplet. Parameters including flow rate, water fraction, and applied detection potential (Edet) were investigated to obtain optimal conditions. Using G-PANI/CPE significantly increased the current response for both cyclic voltammetric detections of ferri/ferrocyanide [Fe(CN)6](3-/4-) (10 times) and 4-AP (2 times), compared to an unmodified electrode. Using the optimized conditions in the droplet system, 4-AP in the presence of PA was selectively determined. The linear range of 4-AP was 50-500 μM (R(2) = 0.99), limit of detection (LOD, S/N = 3) was 15.68 μM, and limit of quantification (LOQ, S/N = 10) was 52.28 μM. Finally, the system was used to determine 4-AP spiked in commercial PA liquid samples and the amounts of 4-AP were found in good agreement with those obtained from the conventional capillary zone electrophoresis/UV-Visible spectrophotometry (CZE/UV-Vis). The proposed microfluidic device could be employed for a high-throughput screening (at least 60 samples h(-1)) of pharmaceutical purity requiring low sample and reagent consumption.
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Affiliation(s)
- Poomrat Rattanarat
- Electrochemistry and Optical Spectroscopy Research Unit (EOSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand
| | - Akkapol Suea-Ngam
- Electrochemistry and Optical Spectroscopy Research Unit (EOSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand; Chromatography and Separation Research Unit (ChSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand
| | - Nipapan Ruecha
- Program in Macromolecular Science, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand
| | - Weena Siangproh
- Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Wattana, Bangkok 10110, Thailand
| | - Charles S Henry
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, United States; School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, United States
| | - Monpichar Srisa-Art
- Electrochemistry and Optical Spectroscopy Research Unit (EOSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand; Chromatography and Separation Research Unit (ChSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand
| | - Orawon Chailapakul
- Electrochemistry and Optical Spectroscopy Research Unit (EOSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand; National Center of Excellent of Petroleum, Petrochemicals and Advanced Materials, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand.
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19
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Wydallis JB, Feeny RM, Wilson W, Kern T, Chen T, Tobet S, Reynolds MM, Henry CS. Spatiotemporal norepinephrine mapping using a high-density CMOS microelectrode array. LAB ON A CHIP 2015; 15:4075-4082. [PMID: 26333296 DOI: 10.1039/c5lc00778j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A high-density amperometric electrode array containing 8192 individually addressable platinum working electrodes with an integrated potentiostat fabricated using Complementary Metal Oxide Semiconductor (CMOS) processes is reported. The array was designed to enable electrochemical imaging of chemical gradients with high spatiotemporal resolution. Electrodes are arranged over a 2 mm × 2 mm surface area into 64 subarrays consisting of 128 individual Pt working electrodes as well as Pt pseudo-reference and auxiliary electrodes. Amperometric measurements of norepinephrine in tissue culture media were used to demonstrate the ability of the array to measure concentration gradients in complex media. Poly(dimethylsiloxane) microfluidics were incorporated to control the chemical concentrations in time and space, and the electrochemical response at each electrode was monitored to generate electrochemical heat maps, demonstrating the array's imaging capabilities. A temporal resolution of 10 ms can be achieved by simultaneously monitoring a single subarray of 128 electrodes. The entire 2 mm × 2 mm area can be electrochemically imaged in 64 seconds by cycling through all subarrays at a rate of 1 Hz per subarray. Monitoring diffusional transport of norepinephrine is used to demonstrate the spatiotemporal resolution capabilities of the system.
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Affiliation(s)
- John B Wydallis
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA.
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20
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Electrochemical droplet-based microfluidics using chip-based carbon paste electrodes for high-throughput analysis in pharmaceutical applications. Anal Chim Acta 2015; 883:45-54. [DOI: 10.1016/j.aca.2015.03.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 02/10/2015] [Accepted: 03/04/2015] [Indexed: 11/27/2022]
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21
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Feeny RM, Wydallis JB, Chen T, Tobet S, Reynolds MM, Henry CS. Analysis of Nitric Oxide from Chemical Donors Using CMOS Platinum Microelectrodes. ELECTROANAL 2015. [DOI: 10.1002/elan.201400510] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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22
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Rattanarat P, Teengam P, Siangproh W, Ishimatsu R, Nakano K, Chailapakul O, Imato T. An Electrochemical Compact Disk-type Microfluidics Platform for Use as an Enzymatic Biosensor. ELECTROANAL 2015. [DOI: 10.1002/elan.201400590] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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23
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Das D, Yan Z, Menon NV, Kang Y, Chan V, Yang C. Continuous detection of trace level concentration of oil droplets in water using microfluidic AC electroosmosis (ACEO). RSC Adv 2015. [DOI: 10.1039/c5ra15624f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A novel design for high throughput detection of oil micro-droplets in water which is important to environmental oil spill monitoring agencies.
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Affiliation(s)
- D. Das
- School of Chemical and Biomedical Engineering
- Nanyang Technological University
- Singapore-637459
- Nanyang Environment and Water Research Institute
- Nanyang Technological University
| | - Z. Yan
- School of Mechanical and Aerospace Engineering
- Nanyang Technological University
- Singapore-639798
| | - N. V. Menon
- School of Chemical and Biomedical Engineering
- Nanyang Technological University
- Singapore-637459
| | - Y. Kang
- School of Chemical and Biomedical Engineering
- Nanyang Technological University
- Singapore-637459
| | - V. Chan
- School of Chemical and Biomedical Engineering
- Nanyang Technological University
- Singapore-637459
| | - C. Yang
- School of Mechanical and Aerospace Engineering
- Nanyang Technological University
- Singapore-639798
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24
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Pluangklang T, Wydallis JB, Cate DM, Nacapricha D, Henry CS. A Simple Microfluidic Electrochemical HPLC Detector for Quantifying Fenton Reactivity from Welding Fumes. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2014; 6:8180-8186. [PMID: 25267929 PMCID: PMC4175734 DOI: 10.1039/c4ay01534g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Development and characterization of a simple microfluidic electrochemical flow cell that can be coupled with HPLC to enable dual absorbance/electrochemical detection is described. Coupling absorbance and electrochemical detection increases the information that can be gathered from a single injection, but a second (typically expensive) detection system is required. Here, an inexpensive, customizable microfluidic electrochemical detector is coupled in series with a commercial HPLC/UV system. The microfluidic device is made from poly(dimethylsiloxane) and contains carbon paste electrodes. To demonstrate the utility of this dual-detection system, the reaction products of the radical scavenging agent salicylic acid and hydroxyl radical generated by Fenton chemistry were analyzed. The dual-detection system was used to quantify 2,5-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, and catechol produced by the addition of H2O2 to filter samples of welding fumes. Measurement recovery was high, with percent recoveries between 97-102%, 92-103%, and 95-103% for 2,5-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, and catechol, respectively, for control samples. The methods described in this work are simple, reliable, and can inexpensively couple electrochemical detection to HPLC-UV systems.
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Affiliation(s)
- Thanakorn Pluangklang
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - John B. Wydallis
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - David M. Cate
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Duangjai Nacapricha
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Charles S. Henry
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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25
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Koehler K, Shapiro J, Sameenoi Y, Henry C, Volckens J. LABORATORY EVALUATION OF A MICROFLUIDIC ELECTROCHEMICAL SENSOR FOR AEROSOL OXIDATIVE LOAD. AEROSOL SCIENCE AND TECHNOLOGY : THE JOURNAL OF THE AMERICAN ASSOCIATION FOR AEROSOL RESEARCH 2014; 48:489-497. [PMID: 24711675 PMCID: PMC3975820 DOI: 10.1080/02786826.2014.891722] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Human exposure to particulate matter (PM) air pollution is associated with human morbidity and mortality. The mechanisms by which PM impacts human health are unresolved, but evidence suggests that PM intake leads to cellular oxidative stress through the generation of reactive oxygen species (ROS). Therefore, reliable tools are needed for estimating the oxidant generating capacity, or oxidative load, of PM at high temporal resolution (minutes to hours). One of the most widely reported methods for assessing PM oxidative load is the dithiothreitol (DTT) assay. The traditional DTT assay utilizes filter-based PM collection in conjunction with chemical analysis to determine the oxidation rate of reduced DTT in solution with PM. However, the traditional DTT assay suffers from poor time resolution, loss of reactive species during sampling, and high limit of detection. Recently, a new DTT assay was developed that couples a Particle-Into-Liquid-Sampler with microfluidic-electrochemical detection. This 'on-line' system allows high temporal resolution monitoring of PM reactivity with improved detection limits. This study reports on a laboratory comparison of the traditional and on-line DTT approaches. An urban dust sample was aerosolized in a laboratory test chamber at three atmospherically-relevant concentrations. The on-line system gave a stronger correlation between DTT consumption rate and PM mass (R2 = 0.69) than the traditional method (R2 = 0.40) and increased precision at high temporal resolution, compared to the traditional method.
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Affiliation(s)
- Kirsten Koehler
- Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, Maryland, USA
| | - Jeffrey Shapiro
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado, USA
| | | | - Charles Henry
- Department of Chemistry, Colorado State University, Fort Collins, Colorado, USA
| | - John Volckens
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado, USA
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26
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Regel A, Lunte S. Integration of a graphite/poly(methyl-methacrylate) composite electrode into a poly(methylmethacrylate) substrate for electrochemical detection in microchips. Electrophoresis 2014; 34:2101-6. [PMID: 23670816 DOI: 10.1002/elps.201300055] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/26/2013] [Accepted: 04/09/2013] [Indexed: 11/05/2022]
Abstract
Traditional fabrication methods for polymer microchips, the bonding of two substrates together to form the microchip, can make the integration of carbon electrodes difficult. We have developed a simple and inexpensive method to integrate graphite/PMMA composite electrodes (GPCEs) into a PMMA substrate. These substrates can be bonded to other PMMA layers using a solvent-assisted thermal bonding method. The optimal composition of the GPCEs for electrochemical detection was determined using cyclic voltammetry with dopamine as a test analyte. Using the optimized GPCEs in an all-PMMA flow cell with flow injection analysis, it was possible to detect 50 nM dopamine under the best conditions. These electrodes were also evaluated for the detection of dopamine and catechol following separation by MCE.
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Affiliation(s)
- Anne Regel
- Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, KS, USA
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27
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Rozniecka E, Jonsson-Niedziolka M, Celebanska A, Niedziolka-Jonsson J, Opallo M. Selective electrochemical detection of dopamine in a microfluidic channel on carbon nanoparticulate electrodes. Analyst 2014; 139:2896-903. [DOI: 10.1039/c3an02207b] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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28
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Electrochemical sensor for selective determination of N-acetylcysteine in the presence of folic acid using a modified carbon nanotube paste electrode. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2013; 33:1078-84. [DOI: 10.1016/j.msec.2012.11.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 09/23/2012] [Accepted: 11/28/2012] [Indexed: 11/17/2022]
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29
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Huo J, Shangguan E, Li Q. A pre-anodized inlaying ultrathin carbon paste electrode for simultaneous determination of uric acid and folic acid. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2012.11.073] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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30
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Mensack MM, Wydallis JB, Lynn NS, Dandy DS, Henry CS. Spatially resolved electrochemical sensing of chemical gradients. LAB ON A CHIP 2013; 13:208-211. [PMID: 23172274 DOI: 10.1039/c2lc41054k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Chemical gradients drive a diverse set of biological processes ranging from nerve transduction to ovulation. At present, the most common method for quantifying chemical gradients is microscopy. Here, a new concept for probing spatial and temporal chemical gradients is reported that uses a multi-layer microfluidic device to measure analyte concentration as a function of lateral position in a microfluidic channel using electrochemistry in a format that is readily adaptable to multi-analyte sensing.
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Affiliation(s)
- Meghan M Mensack
- Department of Chemistry, Colorado State University, 1872 Campus Delivery, Fort Collins, Colorado 80523, USA
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31
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Wongkaew N, Kirschbaum SEK, Surareungchai W, Durst RA, Baeumner AJ. A Novel Three-Electrode System Fabricated on Polymethyl Methacrylate for On-Chip Electrochemical Detection. ELECTROANAL 2012. [DOI: 10.1002/elan.201200336] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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32
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Guan Q, Noblitt SD, Henry CS. Electrophoretic separations in poly(dimethylsiloxane) microchips using mixtures of ionic, nonionic and zwitterionic surfactants. Electrophoresis 2012; 33:2875-83. [PMID: 23019105 PMCID: PMC3804416 DOI: 10.1002/elps.201200255] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The use of surfactant mixtures to affect both EOF and separation selectivity in electrophoresis with PDMS substrates is reported, and capacitively coupled contactless conductivity detection is introduced for EOF measurement on PDMS microchips. First, the EOF was measured for two nonionic surfactants (Tween 20 and Triton X-100), mixed ionic/nonionic surfactant systems (SDS/Tween 20 and SDS/Triton X-100), and finally for the first time, mixed zwitterionic/nonionic surfactant systems (TDAPS/Tween 20 and TDAPS/Triton X-100). EOF for the nonionic surfactants decreased with increasing surfactant concentration. The addition of SDS or TDAPS to a nonionic surfactant increased EOF. After establishing the EOF behavior, the separation of model catecholamines was explored to show the impact on separations. Similar analyte resolution with greater peak heights was achieved with mixed surfactant systems containing Tween 20 and TDAPS relative to the single surfactant system. Finally, the detection of catecholamine release from PC12 cells by stimulation with 80 mM K(+) was performed to demonstrate the usefulness of mixed surfactant systems to provide resolution of biological compounds in complex samples.
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Affiliation(s)
- Qian Guan
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
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33
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Sameenoi Y, Koehler K, Shapiro J, Boonsong K, Sun Y, Collett J, Volckens J, Henry CS. Microfluidic electrochemical sensor for on-line monitoring of aerosol oxidative activity. J Am Chem Soc 2012; 134:10562-8. [PMID: 22651886 PMCID: PMC3397383 DOI: 10.1021/ja3031104] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Particulate matter (PM) air pollution has a significant impact on human morbidity and mortality; however, the mechanisms of PM-induced toxicity are poorly defined. A leading hypothesis states that airborne PM induces harm by generating reactive oxygen species in and around human tissues, leading to oxidative stress. We report here a system employing a microfluidic electrochemical sensor coupled directly to a particle-into-liquid sampler (PILS) system to measure aerosol oxidative activity in an on-line format. The oxidative activity measurement is based on the dithiothreitol (DTT) assay, where, after being oxidized by PM, the remaining reduced DTT is analyzed by the microfluidic sensor. The sensor consists of an array of working, reference, and auxiliary electrodes fabricated in a poly(dimethylsiloxane)-based microfluidic device. Cobalt(II) phthalocyanine-modified carbon paste was used as the working electrode material, allowing selective detection of reduced DTT. The electrochemical sensor was validated off-line against the traditional DTT assay using filter samples taken from urban environments and biomass burning events. After off-line characterization, the sensor was coupled to a PILS to enable on-line sampling/analysis of aerosol oxidative activity. Urban dust and industrial incinerator ash samples were aerosolized in an aerosol chamber and analyzed for their oxidative activity. The on-line sensor reported DTT consumption rates (oxidative activity) in good correlation with aerosol concentration (R(2) from 0.86 to 0.97) with a time resolution of approximately 3 min.
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Affiliation(s)
- Yupaporn Sameenoi
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Kirsten Koehler
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Jeff Shapiro
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Kanokporn Boonsong
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Yele Sun
- Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Jeffrey Collett
- Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, USA
| | - John Volckens
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Charles S. Henry
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA
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34
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Deal KS, Easley CJ. Self-regulated, droplet-based sample chopper for microfluidic absorbance detection. Anal Chem 2012; 84:1510-6. [PMID: 22191400 DOI: 10.1021/ac202791d] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Akin to optical beam chopping, we demonstrate that formation and routing of aqueous droplets in oil can chop a fluidic sample to permit phase sensitive detection. This hand-operated microfluidic sample chopper (μChopper) greatly reduces the detection limit of molecular absorbance in a 27 μm optical path. With direct dependence on path length, absorbance is fundamentally incompatible with microfluidics. While other microfluidic absorbance approaches use complex additions to fabrication, such as fiber coupling and increased optical paths, this self-regulated μChopper uses opposing droplet generators to passively alternate sample and reference droplets at ~10 Hz each. Each droplet's identity is automatically locked-in to its generator, allowing downstream lock-in analysis to nearly eliminate large signal drift or 1/f noise. With a lock-in time constant of 1.9 s and total interrogated volume of 59 nL (122 droplets), a detection limit of 3.0 × 10(-4) absorbance units or 500 nM bromophenol blue (BPB) (29 fmol) was achieved using only an optical microscope and a standard, single-depth (27 μm) microfluidic device. The system was further applied to nanoliter pH sensing and validated with a spectrophotometer. The μChopper represents a fluidic analog to an optical beam chopper, and the self-regulated sample/reference droplet alternation promotes ease of use.
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Affiliation(s)
- Kennon S Deal
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, USA
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