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Mohan JM, Dudala S, Amreen K, Javed A, Dubey SK, Goel S. Microfluidic Device Integrated With PDMS Microchannel and Unmodified ITO Glass Electrodes for Highly Sensitive, Specific, and Point-of-Care Detection of Copper and Mercury. IEEE Trans Nanobioscience 2023; 22:881-888. [PMID: 37022373 DOI: 10.1109/tnb.2023.3241827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This work delves upon developing a two-layer plasma-bonded microfluidic device with a microchannel layer and electrodes for electroanalytical detection of heavy metal ions. The three-electrode system was realized on an ITO-glass slide by suitably etching the ITO layer with the help of CO2 laser. The microchannel layer was fabricated using a PDMS soft-lithography method wherein the mold created by maskless lithography. The optimized dimensions opted to develop a microfluidic device with length of 20 mm, width of 0.5 mm and gap of 1 mm. The device, with bare unmodified ITO electrodes, was tested to detect Cu and Hg by a portable potentiostat connected with a smartphone. The analytes were introduced in the microfluidic device with a peristaltic pump at an optimal flow rate of [Formula: see text]/min. The device exhibited sensitive electro-catalytic sensing of both the metals by achieving an oxidation peak at -0.4 V and 0.1 V for Cu and Hg respectively. Furthermore, square wave voltammetry (SWV) approach was used to analyze the scan rate effect and concentration effect. The device also used to simultaneously detect both the analytes. During simultaneous sensing of Hg and Cu, the linear range was observed between [Formula: see text] to [Formula: see text], the limit of detection (LOD) was found to be [Formula: see text] and [Formula: see text] for Cu and Hg respectively. Further, no interference with other co-existing metal ions was found manifesting the specificity of the device to Cu and Hg. Finally, the device was successfully tested with real samples like tap water, lake water, and serum with remarkable recovery percentages. Such portable devices pave way for detecting various heavy metal ions in a point-of-care environment. The developed device can also be used for detection of other heavy metals like cadmium, lead, zinc etc., by modifying the working electrode with the various nanocomposites.
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Bassi CA, Wu Z, Forst L, Papautsky I. Determination of Mercury with a Miniature Sensor for Point-of-care Testing. ELECTROANAL 2023; 35:e202200234. [PMID: 38894713 PMCID: PMC11185419 DOI: 10.1002/elan.202200234] [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: 05/21/2022] [Accepted: 07/29/2022] [Indexed: 11/09/2022]
Abstract
In developing countries, subsistence gold mining entails mixing metallic mercury with crushed sediments to extract gold. In this approach, the gold-mercury amalgam is heated to evaporate mercury and obtain gold. Thus, the highly volatile mercury can be absorbed through inhalation, resulting in adverse health effects. Urinalysis can be used to detect mercury, which is excreted in urine and feces, and correlate exposure with toxic effects. The current gold standard analytical methods are based on fluorescence or inductively coupled plasma mass spectrometry methods, but are expensive, time consuming, and are not easily accessible in countries where testing is needed. In this work, we report on a miniature electrochemical sensor that can rapidly detect mercury in urine at levels well below the US Biological Exposure Index (BEI) limit of 50 ppb (μg/L). The sensor is based on a thin-film gold electrode and anodic stripping voltammetry electroanalytical approach. The sensor successfully detected mercury at trace levels in urine, with a limit of detection of ~15 ppb Hg in the linear range of 20-80 ppb. With the low-cost disposable sensors and portable instrumentation, it is well suited for point-of-care applications.
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Affiliation(s)
- Caterina Andreasi Bassi
- Department of Biomedical Engineering, University of Illinois Chicago, IL, 851 S. Morgan Street, 218 SEO, Chicago, IL 60607, USA
| | - Zhizhen Wu
- Department of Biomedical Engineering, University of Illinois Chicago, IL, 851 S. Morgan Street, 218 SEO, Chicago, IL 60607, USA
| | - Linda Forst
- Department of Public Health, University of Illinois Chicago, IL, Chicago, IL 60607, USA
| | - Ian Papautsky
- Department of Biomedical Engineering, University of Illinois Chicago, IL, 851 S. Morgan Street, 218 SEO, Chicago, IL 60607, USA
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Wu Z, Rehman A, Zhang Z, Papautsky I. Automatic Microtitrator for Small Volume Samples. ACS MEASUREMENT SCIENCE AU 2022; 2:430-438. [PMID: 36281296 PMCID: PMC9585638 DOI: 10.1021/acsmeasuresciau.2c00021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 06/16/2023]
Abstract
Electroanalytical sensors for point-of-care biomedical or point-of-use environmental sample analysis are gaining popularity due to low limits of detection, ease of miniaturization, convenience, and ability to work with small sample volumes. Since pH must be tightly controlled for optimum electrochemical performance, adjustment of pH in these samples is often a necessity. Yet manual titration is time-consuming and can be especially challenging for small volumes. End point determination can also be difficult. Current commercial automatic pH titrators are generally designed for large volume (>1 mL) batch titrations, while the existing microvolume titrators are semiautomatic at best, still relying on multiple manual steps. To address the gap, we developed an automatic microtitration system suitable for small volume samples. The system was validated using digested whole blood microsamples, successfully demonstrating accurate and rapid pH adjustment for samples as small as 100 μL. The simple modular construction of the system makes it compatible with acid washing for trace metal detection and other cleaning or sample preparation steps. The electrochemical detection of manganese heavy metal in blood at the parts per billion level showed no detectable contamination induced by the system. Ultimately, our simple, accurate, user-friendly automatic microtitration system can be used in the pH adjustment of microvolume samples and can potentially be extended to other pH end point analysis.
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Affiliation(s)
- Zhizhen Wu
- Department
of Biomedical Engineering, University of
Illinois Chicago, Chicago, Illinois 60607, United States
| | - Abid Rehman
- Department
of Bioengineering, University of Illinois
Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Zhehao Zhang
- Department
of Biomedical Engineering, University of
Illinois Chicago, Chicago, Illinois 60607, United States
| | - Ian Papautsky
- Department
of Biomedical Engineering, University of
Illinois Chicago, Chicago, Illinois 60607, United States
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Wu Z, Heineman WR, Haynes EN, Papautsky I. Electrochemical Determination of Manganese in Whole Blood with Indium Tin Oxide Electrode. JOURNAL OF THE ELECTROCHEMICAL SOCIETY 2022; 169:057508. [PMID: 35755409 PMCID: PMC9229665 DOI: 10.1149/1945-7111/ac6a19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In this work, we demonstrate accurate and precise measurement of manganese (Mn) concentration in human whole blood with indium tin oxide (ITO) electrode using square wave stripping voltammetry. While an essential trace metal for human health, elevated levels of Mn due to environmental or occupational exposure have been associated with severe neuromotor dysfunction characterized by parkinsonism and cognitive dysfunction making the monitoring of Mn in whole blood necessary. Pediatric populations are particularly susceptible to Mn given their developing brain and potential long-term impacts on neurodevelopment. The current gold standard for whole blood Mn measurements is by ICP-MS, which is costly and time consuming. The electrochemical detection with ITO working electrode in this work showed a limit of detection of 0.5 μg l-1 and a linear range of 5 to 500 μg l-1, which encompasses the physiological Mn levels in human whole blood (5-18 μg l-1). Our results of Mn measurement in whole blood show an average precision of 96.5% and an average accuracy of 90.3% compared to ICP-MS for both the normal range (5-18 μg l-1) and the elevated levels (>36 μg l-1) that require medical intervention. These results demonstrate the feasibility of Mn measurements in human blood with electrochemical sensors.
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Affiliation(s)
- Zhizhen Wu
- Department of Biomedical Engineering, University of Illinois Chicago, Illinois 60607, USA
| | - William R Heineman
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA
| | - Erin N Haynes
- Department of Epidemiology and Preventive Medicine and Environmental Health, University of Kentucky, Kentucky 40536, USA
| | - Ian Papautsky
- Department of Biomedical Engineering, University of Illinois Chicago, Illinois 60607, USA
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Mc Eleney C, Alves S, Mc Crudden D. Novel magneto-electrochemical determination of Mn(II). J Electroanal Chem (Lausanne) 2021. [DOI: 10.1016/j.jelechem.2021.115734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Boselli E, Wu Z, Friedman A, Henn BC, Papautsky I. Validation of Electrochemical Sensor for Determination of Manganese in Drinking Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:7501-7509. [PMID: 34009956 PMCID: PMC10704915 DOI: 10.1021/acs.est.0c05929] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Manganese (Mn) is an essential nutrient for metabolic functions, yet excessive exposure can lead to neurological disease in adults and neurodevelopmental deficits in children. Drinking water represents one of the routes of excessive Mn exposure. Both natural enrichment from rocks and soil, and man-made contamination can pollute groundwater that supplies drinking water for a substantial fraction of the U.S. population. Conventional methods for Mn monitoring in drinking water are costly and involve a long turn-around time. Recent advancements in electrochemical sensing, however, have led to the development of miniature sensors for Mn determination. These sensors rely on a cathodic stripping voltammetry electroanalytical technique on a miniaturized platinum working electrode. In this study, we validate these electrochemical sensors for the determination of Mn concentrations in drinking water against the standard method using inductively coupled plasma mass spectrometry (ICP-MS). Drinking water samples (n = 78) in the 0.03 ppb to 5.3 ppm range were analyzed. Comparisons with ICP-MS yielded 100% agreement, ∼70% accuracy, and ∼91% precision. We envision the use of our system for rapid and inexpensive point-of-use identification of Mn levels in drinking water, which is especially valuable for frequent monitoring where contamination is present.
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Affiliation(s)
- Elena Boselli
- Department of Bioengineering, University of Illinois at Chicago, IL
| | - Zhizhen Wu
- Department of Bioengineering, University of Illinois at Chicago, IL
| | - Alexa Friedman
- Department of Environmental Health, Boston University School of Public Health, Boston, MA
| | - Birgit Claus Henn
- Department of Environmental Health, Boston University School of Public Health, Boston, MA
| | - Ian Papautsky
- Department of Bioengineering, University of Illinois at Chicago, IL
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Joca JFS, Felix FS, Angnes L. Ultrasonic-Assisted Digestion of Cement and Clinker Samples for the Determination of Manganese by Square Wave Cathodic Stripping Voltammetry. ANAL LETT 2019. [DOI: 10.1080/00032719.2019.1695813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Jhonny F. S. Joca
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, Brazil
- Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Fabiana S. Felix
- Departamento de Química, Universidade Federal de Lavras, Lavras, Brazil
| | - Lúcio Angnes
- Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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Ensch M, Wehring B, Landis GD, Garratt E, Becker MF, Schuelke T, Rusinek CA. Indium Tin Oxide Film Characteristics for Cathodic Stripping Voltammetry. ACS APPLIED MATERIALS & INTERFACES 2019; 11:16991-17000. [PMID: 30932470 DOI: 10.1021/acsami.8b22157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The combination of conductivity, optical transparency, and wide anodic potential window has driven significant interest in indium tin oxide (ITO) as an electrode material for electrochemical measurements. More recently, ITO has been applied to the detection of trace metals using cathodic stripping voltammetry (CSV), specifically manganese (Mn). However, the optimization of ITO fabrication for a voltammetric method such as CSV is yet to be reported, nor have the microstructural properties of ITO been investigated for CSV. Furthermore, CSV does not require optical transparency, thereby allowing nontransparent substrates to be used for deposition. This enables microfabrication procedures to be expanded and simplified compared to glass or quartz. Combining this with the profound importance of sensitive, selective detection of toxic metal ions in environmentally and biologically relevant samples makes ITO especially attractive. In this work, we report a thorough investigation of ITO deposition and processing on silicon (Si) substrates for CSV analysis using Mn as the model analyte. Several ITO process parameters were examined such as heated deposition and post-process annealing. Each ITO film was characterized using a variety of surface, bulk (X-ray diffraction), and electrochemical measurements. Although each ITO film type showed electrochemical activity, the heated and annealed (HA) ITO fabrication process yielded superior results for Mn CSV; a limit of detection (LOD) of 0.1 ppb (1.8 nM) was obtained. This work exemplifies new applications of ITO as an electrode material while providing a baseline for trace detection of toxic metals and other contaminants amenable to detection by CSV.
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Affiliation(s)
- Mary Ensch
- Center for Coatings and Diamond Technologies , Fraunhofer USA, Incorporation , East Lansing , Michigan 48824-1226 , United States
| | - Bettina Wehring
- Center for Coatings and Diamond Technologies , Fraunhofer USA, Incorporation , East Lansing , Michigan 48824-1226 , United States
| | - Greg D Landis
- Center for Coatings and Diamond Technologies , Fraunhofer USA, Incorporation , East Lansing , Michigan 48824-1226 , United States
| | | | - Michael F Becker
- Center for Coatings and Diamond Technologies , Fraunhofer USA, Incorporation , East Lansing , Michigan 48824-1226 , United States
| | - Thomas Schuelke
- Center for Coatings and Diamond Technologies , Fraunhofer USA, Incorporation , East Lansing , Michigan 48824-1226 , United States
| | - Cory A Rusinek
- Center for Coatings and Diamond Technologies , Fraunhofer USA, Incorporation , East Lansing , Michigan 48824-1226 , United States
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