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Oprea A, Weimar U. Gas sensors based on mass-sensitive transducers. Part 2: Improving the sensors towards practical application. Anal Bioanal Chem 2020; 412:6707-6776. [PMID: 32737549 PMCID: PMC7496080 DOI: 10.1007/s00216-020-02627-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 02/24/2020] [Accepted: 03/27/2020] [Indexed: 01/03/2023]
Abstract
Within the framework outlined in the first part of the review, the second part addresses attempts to increase receptor material performance through the use of sensor systems and chemometric methods, in conjunction with receptor preparation methods and sensor-specific tasks. Conclusions are then drawn, and development perspectives for gravimetric sensors are discussed.
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Affiliation(s)
- Alexandru Oprea
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University, Tübingen, Germany.
- Center for Light-Matter Interaction, Sensors & Analytics, Eberhard Karls University, Auf der Morgenstelle 15, 72076, Tübingen, Germany.
| | - Udo Weimar
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University, Tübingen, Germany
- Center for Light-Matter Interaction, Sensors & Analytics, Eberhard Karls University, Auf der Morgenstelle 15, 72076, Tübingen, Germany
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2
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Quartz Crystal Microbalance Based Sensor Arrays for Detection and Discrimination of VOCs Using Phosphonium Ionic Liquid Composites. SENSORS 2020; 20:s20030615. [PMID: 31979151 PMCID: PMC7037595 DOI: 10.3390/s20030615] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/15/2020] [Accepted: 01/20/2020] [Indexed: 11/17/2022]
Abstract
Herein, we examine two sensing schemes for detection and discrimination of chlorinated volatile organic compounds (VOCs). In this work, phosphonium ionic liquids (ILs) were synthesized and vapor sensing properties examined and compared to phosphonium IL-polymer composites. Pure IL sensors were used to develop a QCM-based multisensory array (MSA), while IL-polymer composites were used to develop an MSA and virtual sensor arrays (VSAs). It was found that by employing the composite MSA, five chlorinated VOCs were accurately discriminated at 95.56%, which was an increase in accuracy as compared to pure ILs MSA (84.45%). Data acquired with two out of three VSAs allowed discrimination of chlorinated VOCs with 100% accuracy. These studies have provided greater insight into the benefits of incorporating polymers in coating materials for enhanced discrimination accuracies of QCM-based sensor arrays. To the best of our knowledge, this is the first report of a QCM-based VSA for discrimination of closely related chlorinated VOCs.
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3
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Bulk and Surface Acoustic Wave Sensor Arrays for Multi-Analyte Detection: A Review. SENSORS 2019; 19:s19245382. [PMID: 31817599 PMCID: PMC6960530 DOI: 10.3390/s19245382] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/28/2019] [Accepted: 11/29/2019] [Indexed: 01/05/2023]
Abstract
Bulk acoustic wave (BAW) and surface acoustic wave (SAW) sensor devices have successfully been used in a wide variety of gas sensing, liquid sensing, and biosensing applications. Devices include BAW sensors using thickness shear modes and SAW sensors using Rayleigh waves or horizontally polarized shear waves (HPSWs). Analyte specificity and selectivity of the sensors are determined by the sensor coatings. If a group of analytes is to be detected or if only selective coatings (i.e., coatings responding to more than one analyte) are available, the use of multi-sensor arrays is advantageous, as the evaluation of the resulting signal patterns allows qualitative and quantitative characterization of the sample. Virtual sensor arrays utilize only one sensor but combine it with enhanced signal evaluation methods or preceding sample separation, which results in similar results as obtained with multi-sensor arrays. Both array types have shown to be promising with regard to system integration and low costs. This review discusses principles and design considerations for acoustic multi-sensor and virtual sensor arrays and outlines the use of these arrays in multi-analyte detection applications, focusing mainly on developments of the past decade.
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4
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Liu R, Li Z, Huang Z, Li K, Lv Y. Biosensors for explosives: State of art and future trends. Trends Analyt Chem 2019. [DOI: 10.1016/j.trac.2019.05.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Zeng G, Wu C, Chang Y, Zhou C, Chen B, Zhang M, Li J, Duan X, Yang Q, Pang W. Detection and Discrimination of Volatile Organic Compounds using a Single Film Bulk Acoustic Wave Resonator with Temperature Modulation as a Multiparameter Virtual Sensor Array. ACS Sens 2019; 4:1524-1533. [PMID: 31132253 DOI: 10.1021/acssensors.8b01678] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This paper describes the detection and discrimination of volatile organic compounds (VOCs) using an e-nose system based on a multiparameter virtual sensor array (VSA), which consists of a single-chip temperature-compensated film bulk acoustic wave resonator (TC-FBAR) coated with 20-bilayer self-assembled poly(sodium 4-styrenesulfonate)/poly(diallyldimethylammonium chloride) thin films. The high-frequency and microscale FBAR multiparameter VSA was realized by temperature modulation, which can greatly reduce the cost and complexity compared to those of a traditional e-nose system and can allow it to operate at different temperatures. The discrimination effect depends on the synergy of temperature modulation and the sensing material. For proof-of-concept validation purposes, the TC-FBAR was exposed to six different VOC vapors at six different gas partial pressures by real-time VOC static detection and dynamic detection. The resulting frequency shifts and impedance responses were measured at different temperatures and evaluated using principal component analysis and linear discriminant analysis, which revealed that all analytes can be distinguished and classified with more than 97% accuracy. To the best of our knowledge, this report is the first on an FBAR multiparameter VSA based on temperature modulation, and the proposed novel VSA shows great potential as a compact and promising e-nose system integrated in commercial electronic products.
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Affiliation(s)
| | - Chen Wu
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | | | | | | | | | - Jiuyan Li
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
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6
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Vaughan SR, Speller NC, Chhotaray P, McCarter KS, Siraj N, Pérez RL, Li Y, Warner IM. Class specific discrimination of volatile organic compounds using a quartz crystal microbalance based multisensor array. Talanta 2018; 188:423-428. [PMID: 30029397 DOI: 10.1016/j.talanta.2018.05.097] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 05/28/2018] [Accepted: 05/30/2018] [Indexed: 11/29/2022]
Abstract
The use of quartz crystal microbalance (QCM) sensor arrays for analyses of volatile organic compounds (VOC) has attracted significant interest in recent years. In this regard, a group of uniformed materials based on organic salts (GUMBOS) has proven to be promising recognition elements in QCM based sensor arrays due to diverse properties afforded by this class of tunable materials. Herein, we examine the application of four novel phthalocyanine based GUMBOS as recognition elements for VOC sensing using a QCM based multisensor array (MSA). These synthesized GUMBOS are composed of copper (II) phthalocyaninetetrasulfonate (CuPcS4) anions coupled with ammonium or phosphonium cations respectively (tetrabutylammonium (TBA), tetrabutylphosphonium (P4444), 3-(dodecyldimethyl-ammonio)propanesulfonate (DDMA), and tributyl-n-octylphosphonium (P4448)). These materials were characterized using ESI-MS and FTIR, while thermal properties were investigated using TGA. Vapor sensing properties of these GUMBOS towards a set of common VOCs at three sample flow rate ratios were examined. Upon exposure to VOCs, each sensor generated analyte specific response patterns that were recorded and analyzed using principal component and discriminant analyses. Use of this MSA allowed discrimination of analytes into different functional group classes (alcohols, chlorohydrocarbons, aromatic hydrocarbons, and hydrocarbons) with 98.6% accuracy. Evaluation of these results provides further insight into the use of phthalocyanine GUMBOS as recognition elements for QCM-based MSAs for VOC discrimination.
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Affiliation(s)
- Stephanie R Vaughan
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Nicholas C Speller
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA; Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Pratap Chhotaray
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA; Department of Chemistry, Indian Institute of Technology Delhi, Delhi 110016, India
| | - Kevin S McCarter
- Department of Experimental Statistics, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Noureen Siraj
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA; Department of Chemistry, University of Arkansas at Little Rock, Little Rock, AR 72204, USA
| | - Rocío L Pérez
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Yue Li
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Isiah M Warner
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
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7
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Prospects of ionic liquids application in electronic and bioelectronic nose instruments. Trends Analyt Chem 2017. [DOI: 10.1016/j.trac.2017.05.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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8
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Tao W, Lin P, Liu S, Xie Q, Ke S, Zeng X. 1-Butyl-3-Methylimidazolium Tetrafluoroborate Film as a Highly Selective Sensing Material for Non-Invasive Detection of Acetone Using a Quartz Crystal Microbalance. SENSORS 2017; 17:s17010194. [PMID: 28117697 PMCID: PMC5298767 DOI: 10.3390/s17010194] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 01/08/2017] [Accepted: 01/13/2017] [Indexed: 01/12/2023]
Abstract
Breath acetone serves as a biomarker for diabetes. This article reports 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]), a type of room temperature ionic liquid (RTIL), as a selective sensing material for acetone. The RTIL sensing layer was coated on a quartz crystal microbalance (QCM) for detection. The sensing mechanism is based on a decrease in viscosity and density of the [bmim][BF₄] film due to the solubilization of acetone leading to a positive frequency shift in the QCM. Acetone was detected with a linear range from 7.05 to 750 ppmv. Sensitivity and limit of detection were found to be 3.49 Hz/ppmv and 5.0 ppmv, respectively. The [bmim][BF₄]-modified QCM sensor demonstrated anti-interference ability to commonly found volatile organic compounds in breath, e.g., isoprene, 1,2-pentadiene, d-limonene, and dl-limonene. This technology is useful for applications in non-invasive early diabetic diagnosis.
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Affiliation(s)
- Wenyan Tao
- Shenzhen Key Laboratory of Special Functional Materials & Shenzhen Engineering Laboratory for Advance Technology of Ceramics, College of Materials Science and Engineering, Shenzhen University, Shenzhen 510081, China.
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Peng Lin
- Shenzhen Key Laboratory of Special Functional Materials & Shenzhen Engineering Laboratory for Advance Technology of Ceramics, College of Materials Science and Engineering, Shenzhen University, Shenzhen 510081, China.
| | - Sili Liu
- Department of Biomedical Engineering, the Chinese University of Hong Kong, Shatin, Hong Kong 999077, China.
| | - Qingji Xie
- College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410082, China.
| | - Shanming Ke
- Shenzhen Key Laboratory of Special Functional Materials & Shenzhen Engineering Laboratory for Advance Technology of Ceramics, College of Materials Science and Engineering, Shenzhen University, Shenzhen 510081, China.
| | - Xierong Zeng
- Shenzhen Key Laboratory of Special Functional Materials & Shenzhen Engineering Laboratory for Advance Technology of Ceramics, College of Materials Science and Engineering, Shenzhen University, Shenzhen 510081, China.
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
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Lin L, Rehman A, Chi X, Zeng X. 2,4-Toluene diisocyanate detection in liquid and gas environments through electrochemical oxidation in an ionic liquid. Analyst 2016; 141:1519-29. [PMID: 26763507 PMCID: PMC4756716 DOI: 10.1039/c5an02220g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electrochemical oxidation of 2,4-toluene diisocyanate (2,4-TDI) in an ionic liquid (IL) has been systematically characterized to determine plausible electrochemical and chemical reaction mechanisms and to define the optimal detection methods for such a highly significant analyte. It has been found that the use of an IL as the electrolyte allows the oxidation of 2,4-TDI to occur at a less positive anodic potential with no side reactions as compared to traditional acetonitrile based electrolytes. UV-Vis, FT-IR, cyclic voltammetry and Electrochemical Impedance Spectroscopy (EIS) studies have revealed the unique mechanisms of dimerization of 2,4-TDI at the electrode interface by self-addition reactions, which can be utilized to improve the selectivity of detection. The study of 2,4-TDI redox chemistry further facilitates the development of a robust amperometric sensing methodology by selecting a hydrophobic IL ([C4mpy][NTf2]) and by restricting the potential window to only include the oxidation process. Thus, this innovative electrochemical sensor is capable of avoiding the two most ubiquitous interferents in ambient conditions (i.e. humidity and oxygen), thereby enhancing the sensor performance and reliability for real world applications. The method was established to detect 2,4-TDI in both liquid and gas phases. The limits of detection (LOD) values were 130.2 ppm and 0.7862 ppm, respectively, for the two phases, and are comparable to the safety standards reported by NIOSH. The as-developed 2.4-TDI amperometric sensor exhibits a sensitivity of 1.939 μA ppm(-1). Moreover, due to the simplicity of design and the use of an IL both as a solvent and non-volatile electrolyte, the sensor has the potential to be miniaturized for smart sensing protocols in distributed sensor applications.
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Affiliation(s)
- Lu Lin
- Department of Chemistry, Oakland University, Rochester, MI 48309, USA.
| | - Abdul Rehman
- Department of Chemistry, Oakland University, Rochester, MI 48309, USA.
| | - Xiaowei Chi
- Department of Chemistry, Oakland University, Rochester, MI 48309, USA.
| | - Xiangqun Zeng
- Department of Chemistry, Oakland University, Rochester, MI 48309, USA.
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10
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Speller NC, Siraj N, Vaughan S, Speller LN, Warner IM. Assessment of QCM array schemes for mixture identification: citrus scented odors. RSC Adv 2016. [DOI: 10.1039/c6ra16988k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
A comparative study of QCM based MSAs, VSAs, and V-MSAs for complex mixture analysis.
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Affiliation(s)
| | - Noureen Siraj
- Department of Chemistry
- University of Arkansas at Little Rock
- Little Rock
- USA
| | | | - Lauren N. Speller
- College of Arts and Sciences
- Washington University in St. Louis
- St. Louis
- USA
| | - Isiah M. Warner
- Department of Chemistry
- Louisiana State University
- Baton Rouge
- USA
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11
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Bragazzi NL, Amicizia D, Panatto D, Tramalloni D, Valle I, Gasparini R. Quartz-Crystal Microbalance (QCM) for Public Health: An Overview of Its Applications. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 101:149-211. [PMID: 26572979 DOI: 10.1016/bs.apcsb.2015.08.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nanobiotechnologies, from the convergence of nanotechnology and molecular biology and postgenomics medicine, play a major role in the field of public health. This overview summarizes the potentiality of piezoelectric sensors, and in particular, of quartz-crystal microbalance (QCM), a physical nanogram-sensitive device. QCM enables the rapid, real time, on-site detection of pathogens with an enormous burden in public health, such as influenza and other respiratory viruses, hepatitis B virus (HBV), and drug-resistant bacteria, among others. Further, it allows to detect food allergens, food-borne pathogens, such as Escherichia coli and Salmonella typhimurium, and food chemical contaminants, as well as water-borne microorganisms and environmental contaminants. Moreover, QCM holds promises in early cancer detection and screening of new antiblastic drugs. Applications for monitoring biohazards, for assuring homeland security, and preventing bioterrorism are also discussed.
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Affiliation(s)
- Nicola Luigi Bragazzi
- Department of Health Sciences (DISSAL), Via Antonio Pastore 1, University of Genoa, Genoa, Italy
| | - Daniela Amicizia
- Department of Health Sciences (DISSAL), Via Antonio Pastore 1, University of Genoa, Genoa, Italy
| | - Donatella Panatto
- Department of Health Sciences (DISSAL), Via Antonio Pastore 1, University of Genoa, Genoa, Italy
| | - Daniela Tramalloni
- Department of Health Sciences (DISSAL), Via Antonio Pastore 1, University of Genoa, Genoa, Italy
| | - Ivana Valle
- SSD "Popolazione a rischio," Health Prevention Department, Local Health Unit ASL3 Genovese, Genoa, Italy
| | - Roberto Gasparini
- Department of Health Sciences (DISSAL), Via Antonio Pastore 1, University of Genoa, Genoa, Italy.
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12
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Rehman A, Zeng X. Methods and approaches of utilizing ionic liquids as gas sensing materials. RSC Adv 2015; 5:58371-58392. [PMID: 29142738 PMCID: PMC5683717 DOI: 10.1039/c5ra06754e] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Gas monitoring is of increasing significance for a broad range of applications in the fields of environmental and civil infrastructures, climate and energy, health and safety, industry and commerce. Even though there are many gas detection devices and systems available, the increasing needs for better detection technologies that not only satisfy the high analytical standards but also meet additional device requirements (e.g., being robust to survive under field conditions, low cost, small, smart, more mobile), demand continuous efforts in developing new methods and approaches for gas detection. Ionic Liquids (ILs) have attracted a tremendous interest as potential sensing materials for the gas sensor development. Being composed entirely of ions and with a broad structural and functional diversity, i.e., bifunctional (organic/inorganic), biphasic (solid/liquid) and dual-property (solvent/electrolyte), they have the complementing attributes and the required variability to allow a systematic design process across many sensing components to enhance sensing capability especially for miniaturized sensor system implementation. The emphasis of this review is to describe molecular design and control of IL interface materials to provide selective and reproducible response and to synergistically integrate IL sensing materials with low cost and low power electrochemical, piezoelectric/QCM and optical transducers to address many gas detection challenges (e.g., sensitivity, selectivity, reproducibility, speed, stability, cost, sensor miniaturization, and robustness). We further show examples to justify the importance of understanding the mechanisms and principles of physicochemical and electrochemical reactions in ILs and then link those concepts to developing new sensing methods and approaches. By doing this, we hope to stimulate further research towards the fundamental understanding of the sensing mechanisms and new sensor system development and integration, using simple sensing designs and flexible sensor structures both in terms of scientific operation and user interface that can be miniaturized and interfaced with modern wireless monitoring technologies to achieve specifications heretofore unavailable on current markets for the next generation of gas sensor applications.
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Speller NC, Siraj N, Regmi BP, Marzoughi H, Neal C, Warner IM. Rational Design of QCM-D Virtual Sensor Arrays Based on Film Thickness, Viscoelasticity, and Harmonics for Vapor Discrimination. Anal Chem 2015; 87:5156-66. [DOI: 10.1021/ac5046824] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nicholas C. Speller
- Department of Chemistry, ‡Department of Information Systems and Decision Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Noureen Siraj
- Department of Chemistry, ‡Department of Information Systems and Decision Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Bishnu P. Regmi
- Department of Chemistry, ‡Department of Information Systems and Decision Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Hassan Marzoughi
- Department of Chemistry, ‡Department of Information Systems and Decision Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Courtney Neal
- Department of Chemistry, ‡Department of Information Systems and Decision Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Isiah M. Warner
- Department of Chemistry, ‡Department of Information Systems and Decision Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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14
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Lin Z, Shelby ML, Hayes D, Fransted KA, Chen LX, Allen MJ. Water-exchange rates of lanthanide ions in an ionic liquid. Dalton Trans 2014; 43:16156-9. [PMID: 25271702 PMCID: PMC11009877 DOI: 10.1039/c4dt02492c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
The first ligand-exchange rate measurements of lanthanide ions in an ionic liquid are reported here. The trend of water-exchange rates in the ionic liquid is the opposite of the trend in water.
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Affiliation(s)
- Zhijin Lin
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, USA.
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15
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Benedetti TM, Torresi RM. Rheological changes and kinetics of water uptake by poly(ionic liquid)-based thin films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:15589-15595. [PMID: 24289223 DOI: 10.1021/la4038809] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Water uptake by thin films composed of the poly(ionic liquid) poly[diallyldimethylammonium bis(trifluoromethanesulfonyl)imide] (PDDATf2N) and the ionic liquid N,N-butylmethylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr1.4Tf2N) was studied with a quartz crystal microbalance with dissipation. The data obtained for films with different compositions during the passage of dry and wet N2 flow through the films were simulated with the Kevin-Voigt viscoelastic model for assessment of the mass of uptake water as well as the viscoelastic parameters. Our results show that the ionic liquid acts as a plasticizer, reducing the rigidity of the film and decreasing the capacity of water uptake. Introduction to a Li salt (LiTf2N) increases the water uptake capacity and also affects both elastic and viscous parameters due to aggregation among the ions from the ionic liquid and Li(+). However, due to the preferable interaction of Li(+) ions with water molecules, these aggregates are broken when the film is hydrated. In short, the presence of water in such films affects their mechanical properties, which can reflect in their performances as solid state electrolytes and ion-conducting membranes for electrochemical applications.
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Affiliation(s)
- Tânia M Benedetti
- Instituto de Química, Universidade de São Paulo (USP) , CP 26077, 05513-970, São Paulo-SP, Brazil
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16
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Toniolo R, Pizzariello A, Dossi N, Lorenzon S, Abollino O, Bontempelli G. Room temperature ionic liquids as useful overlayers for estimating food quality from their odor analysis by quartz crystal microbalance measurements. Anal Chem 2013; 85:7241-7. [PMID: 23808811 DOI: 10.1021/ac401151m] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An array of quartz crystals coated with different room-temperature ionic liquids (RTILs) is proposed for the analysis of flavors by quartz crystal microbalance (QCM) measurements. Seven RTILs were adopted as sensing layers, all containing imidazolium or phosphonium cations, differing from one another in the length and branching of alkyl groups and neutralized by different anions. The array was at first applied to the analysis of 31 volatile organic compounds (VOCs), such as alcohols, phenols, aldehydes, esters, ketones, acids, amines, hydrocarbons and terpenes, chosen as representative components of a wide variety of food flavors. Multivariate data analysis by the principal component analysis (PCA) approach of the set of the corresponding responses led to separated clusters for these different chemical categories. To further prove the good performance of the RTIL-coated quartz crystal array as an "electronic nose", it was applied to the analysis of headspaces from cinnamon samples belonging to different botanical varieties ( Cinnamon zeylanicum and Cinnamon cassia ). PCA applied to responses recorded on different stocks of samples of both varieties showed that they could be fully discriminated.
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Affiliation(s)
- Rosanna Toniolo
- Department of Food Science, University of Udine, Udine, Italy.
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17
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Rehman A, Zeng X. Ionic liquids as green solvents and electrolytes for robust chemical sensor development. Acc Chem Res 2012; 45:1667-77. [PMID: 22891895 DOI: 10.1021/ar200330v] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ionic liquids (ILs) exhibit complex behavior. Their simultaneous dual nature as solvents and electrolytes supports the existence of structurally tunable cations and anions, which could provide the basis of a novel sensing technology. However, the elucidation of the physiochemical properties of ILs and their connections with the interaction and redox mechanisms of the target analytes requires concerted data acquired from techniques including spectroscopic investigations, thermodynamic and solvation models, and molecular simulations. Our laboratory is using these techniques for the rational design and selection of ILs and their composites that could serve as the recognition elements in various sensing platforms. ILs show equal utility in both piezoelectric and electrochemical formats through functionalized ionics that provide orthogonal chemo- and regioselectivity. In this Account, we summarize recent developments in and applications of task-specific ILs and their surface immobilization on solid supports. Such materials can serve as a replacement for conventional recognition elements and electrolytic media in piezoelectric and electrochemical sensing approaches, and we place a special focus on our contributions to these fields. ILs take advantage of both the physical and chemical forces of interaction and can incorporate various gas analytes. Exploiting these features, we have designed piezoelectric sensors and sensor arrays for high-temperature applications. Vibrational spectroscopy of these ILs reveals that hydrogen bonding and dipole-dipole interactions are typically responsible for the observed sensing profiles, but the polarization and cavity formation effect as an analyte approaches the recognition matrix can also cause selective discrimination. IL piezoelectric sensors can have low sensitivity and reproducibility. To address these issues, we designed IL/conducting polymer host systems that tune existing molecular templates with highly selective structure specific interactions. We can also modulate the IL microenvironment so that ILs act as filler molecules to optimize host template cavity size, shape, and functionality. When used as non-volatile and tunable electrolytes, ILs show great potential for the development of both amperometric and electrochemical double layer capacitance sensors for the detection of oxygen and explosives. We also designed and tested a two dimensional electrode chip that enabled simultaneous monitoring of both piezoelectric and electrochemical signals. This device imparted additional selectivity and overcame the limitations of the typical sensing protocol. The integrated piezoelectric and electrochemical sensing approach allows the measure of the charge to mass ratio under a dynamic regime. The electrogravimetric dynamic relationship allows for further discrimination between and accurate quantification of the interfacial transfer of different species. In summary, although new systematic and mechanistic studies of ILs are needed, we show that the self-organized phases of the aggregated non-polar and charged domains of ILs are useful sensing materials for electrochemical and quartz crystal microbalance transducers.
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Affiliation(s)
- Abdul Rehman
- The Department of Chemistry, Oakland University, Rochester, Michigan 48309, United States
| | - Xiangqun Zeng
- The Department of Chemistry, Oakland University, Rochester, Michigan 48309, United States
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Xiao C, Rehman A, Zeng X. Dynamics of Redox Processes in Ionic Liquids and Their Interplay for Discriminative Electrochemical Sensing. Anal Chem 2012; 84:1416-24. [DOI: 10.1021/ac2024798] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chunhui Xiao
- The Department of Chemistry, Oakland University, Rochester, Michigan 48309, United
States
- State Key Laboratory
of Chemo/Biosensing
and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Abdul Rehman
- The Department of Chemistry, Oakland University, Rochester, Michigan 48309, United
States
| | - Xiangqun Zeng
- The Department of Chemistry, Oakland University, Rochester, Michigan 48309, United
States
| |
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