1
|
Choi KR, Honig ML, Bühlmann P. Covalently attached ionophores extend the working range of potentiometric pH sensors with poly(decyl methacrylate) sensing membranes. Analyst 2024; 149:1132-1140. [PMID: 38205703 DOI: 10.1039/d3an02047a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
The pH working range of solid-contact ion-selective electrodes (ISEs) with plasticizer-free poly(decyl methacrylate) sensing membranes is shown to be expanded by covalent attachment of H+ ionophores to the polymeric membrane matrix. In situ photopolymerization not only incorporates the ionophores into the polymer backbone, but at the same time also attaches the sensing membranes covalently to the underlying inert polymer and nanographite solid contact, minimizing sensor drift and preventing failure by membrane delamination. A new pyridine-based H+ ionophore, 3-(pyridine-3-yl)propyl methacrylate, has lower basicity than trialkylamine ionophores and expands the upper detection limit. This reduces in particular the interference from hydrogen phthalate, which is a common component of commercial pH buffers. Moreover, the lower detection limit is improved by replacing the CH2CH2 spacer of previously reported dialkylaminoethyl methacrylates with a (CH2)10 spacer, which increases its basicity. Notably, for the more basic and highly cation-selective ionophore 10-(diisopropylamino)decyl methacrylate, the extent of counterion interference from hydrogen phthalate shifted the upper detection limit to lower pH by nearly one pH unit when the crosslinker concentration was decreased.
Collapse
Affiliation(s)
- Kwangrok R Choi
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455, USA.
| | - Madeline L Honig
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455, USA.
| | - Philippe Bühlmann
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455, USA.
| |
Collapse
|
2
|
Choi KR, Chen XV, Hu J, Bühlmann P. Solid-Contact pH Sensor with Covalent Attachment of Ionophores and Ionic Sites to a Poly(decyl methacrylate) Matrix. Anal Chem 2021; 93:16899-16905. [PMID: 34878238 DOI: 10.1021/acs.analchem.1c03985] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
With a view to improving the sensor lifetime, solid-contact ion-selective electrodes (ISEs) were prepared with a plasticizer-free and cross-linked poly(decyl methacrylate) matrix, to which only the ionic sites, only the ionophore, or both the ionic sites and ionophore were covalently attached. In earlier work with covalently attached ionophores or ionic sites, it was difficult to discount the presence of ionophores or ionic site impurities that were not covalently attached to the polymer backbone because the reagents used to introduce the ionophore or ionic sites had high hydrophobicities. In this work, we deliberately chose readily available hydrophilic reagents for the introduction of covalently attached H+ ionophores with tertiary amino groups and covalently attached sulfonate groups as ionic sites. This simplified the synthesis and made it possible to thoroughly remove ionophores and ionic sites not covalently attached to the polymer backbone. Our results confirm the expectation that hydrophobic ISE membranes with both covalently attached ionophores and ionic sites have impractically long response times. In contrast, ISEs with either covalently attached H+ ionophores or covalently attached ionic sites responded to pH with quick Nernstian responses and high selectivity. Both conventional plasticized poly(vinyl chloride) (PVC)-based ISEs and the new poly(decyl methacrylate) membranes were exposed to 90 °C heat for 2 h, 10% ethanol for 1 day, or undiluted blood serum for 5 days. In all three cases, the poly(decyl methacrylate) ISEs exhibited properties superior to conventional PVC-based ISEs, confirming the advantages of the covalent attachment.
Collapse
Affiliation(s)
- Kwangrok R Choi
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis Minnesota 55455, United States
| | - Xin V Chen
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis Minnesota 55455, United States
| | - Jinbo Hu
- Emerson Automation Solutions, 6021 Innovation Blvd, Shakopee Minnesota 55379, United States
| | - Philippe Bühlmann
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis Minnesota 55455, United States
| |
Collapse
|
3
|
Mahmoud Mostafa S, Ali Farghali A, Magdy Khalil M. Novel Zn‐Fe LDH/MWCNT
s
and Graphene/MWCNTs Nanocomposites Based Potentiometric Sensors for Benzydamine Determination in Biological Fluids and Real Water Samples. ELECTROANAL 2021. [DOI: 10.1002/elan.202060455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Ahmed Ali Farghali
- Materials Science and Nanotechnology Department Faculty of Postgraduate Studies for Advanced Sciences Beni-Suef University Beni-Suef Egypt
| | | |
Collapse
|
4
|
Jeszke M, Trzciński K, Karczewski J, Luboch E. Investigation of poly(3,4-ethylenedioxythiophene) deposition method influence on properties of ion-selective electrodes based on bis(benzo-15-crown-5) derivatives. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2017.05.197] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
5
|
Yin T, Li J, Qin W. An All-solid-state Polymeric Membrane Ca2+-selective Electrode Based on Hydrophobic Alkyl-chain-functionalized Graphene Oxide. ELECTROANAL 2016. [DOI: 10.1002/elan.201600383] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Tanji Yin
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation; Yantai Institute of Coastal Zone Research (YIC); Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Environmental Processes, YICCAS; Yantai Shandong 264003 P. R. China
| | - Jinghui Li
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation; Yantai Institute of Coastal Zone Research (YIC); Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Environmental Processes, YICCAS; Yantai Shandong 264003 P. R. China
- University of the Chinese Academy of Sciences; Beijing 100049 P. R. China
| | - Wei Qin
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation; Yantai Institute of Coastal Zone Research (YIC); Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Environmental Processes, YICCAS; Yantai Shandong 264003 P. R. China
| |
Collapse
|
6
|
Pechenkina IA, Mikhelson KN. Materials for the ionophore-based membranes for ion-selective electrodes: Problems and achievements (review paper). RUSS J ELECTROCHEM+ 2015. [DOI: 10.1134/s1023193515020111] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
7
|
Johns VK, Patel PK, Hassett S, Calvo-Marzal P, Qin Y, Chumbimuni-Torres KY. Visible Light Activated Ion Sensing Using a Photoacid Polymer for Calcium Detection. Anal Chem 2014; 86:6184-7. [DOI: 10.1021/ac500956j] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Valentine K. Johns
- Department
of Chemistry, Eastern Kentucky University, Richmond, Kentucky 40475, United States
| | - Parth K. Patel
- Department
of Chemistry, University of Central Florida, Orlando, Florida 32816-2366, United States
| | - Shelly Hassett
- Department
of Chemistry, University of Central Florida, Orlando, Florida 32816-2366, United States
| | - Percy Calvo-Marzal
- Department
of Chemistry, University of Central Florida, Orlando, Florida 32816-2366, United States
| | - Yu Qin
- School
of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210093, China
| | | |
Collapse
|
8
|
Fluorescent nanoparticles for intracellular sensing: A review. Anal Chim Acta 2012; 751:1-23. [DOI: 10.1016/j.aca.2012.09.025] [Citation(s) in RCA: 237] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 09/13/2012] [Accepted: 09/16/2012] [Indexed: 12/31/2022]
|
9
|
Ling JLW, Ab Ghani S. Poly(4-vinylpyridine-co-aniline)-modified electrode—synthesis, characterization, and application as cadmium(II) ion sensor. J Solid State Electrochem 2012. [DOI: 10.1007/s10008-012-1910-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
10
|
Alkan C, Ensari ÖF, Kahraman D. Poly(2-alkyloyloxyethylacrylate) and poly(2-alkyloyloxyethylacrylate-co-methylacrylate) comblike polymers as novel phase-change materials for thermal energy storage. J Appl Polym Sci 2012. [DOI: 10.1002/app.36646] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
11
|
Wilson D, Abbas MN, Radwan ALA, del Valle M. Potentiometric electronic tongue to resolve mixtures of sulfide and perchlorate anions. SENSORS (BASEL, SWITZERLAND) 2011; 11:3214-26. [PMID: 22163795 PMCID: PMC3231598 DOI: 10.3390/s110303214] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 02/24/2011] [Accepted: 03/10/2011] [Indexed: 11/16/2022]
Abstract
This work describes the use of an array of potentiometric sensors and an artificial neural network response model to determine perchlorate and sulfide ions in polluted waters, by what is known as an electronic tongue. Sensors used have been all-solid-state PVC membrane selective electrodes, where their ionophores were different metal-phtalocyanine complexes with specific and anion generic responses. The study case illustrates the potential use of electronic tongues in the quantification of mixtures when interfering effects need to be counterbalanced: relative errors in determination of individual ions can be decreased typically from 25% to less than 5%, if compared to the use of a single proposed ion-selective electrode.
Collapse
Affiliation(s)
- Deivy Wilson
- Sensors and Biosensors Group, Department of Chemistry, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain; E-Mail:
| | - Mohammed N. Abbas
- Analytical Laboratory, National Research Centre, Dokki, Cairo, Egypt; E-Mails: (M.N.A.); (A.L.A.R.)
| | - Abdel Latief A. Radwan
- Analytical Laboratory, National Research Centre, Dokki, Cairo, Egypt; E-Mails: (M.N.A.); (A.L.A.R.)
| | - Manel del Valle
- Sensors and Biosensors Group, Department of Chemistry, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain; E-Mail:
| |
Collapse
|
12
|
Peper S, Gonczy C. Potentiometric Response Characteristics of Membrane-BasedCs+-Selective Electrodes Containing Ionophore-Functionalized Polymeric Microspheres. INTERNATIONAL JOURNAL OF ELECTROCHEMISTRY 2011. [DOI: 10.4061/2011/276896] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cs+-selective solvent polymeric membrane-based ion-selective electrodes (ISEs) were developed by doping ethylene glycol-functionalized cross-linked polystyrene microspheres (P-EG) into a plasticized poly(vinyl chloride) (PVC) matrix containing sodium tetrakis-(3,5-bis(trifluoromethyl)phenyl) borate (TFPB) as the ion exchanger. A systematic study examining the effects of the membrane plasticizers bis(2-ethylhexyl) sebacate (DOS), 2-nitrophenyl octyl ether (NPOE), and 2-fluorophenyl nitrophenyl ether (FPNPE) on the potentiometric response and selectivity of the corresponding electrodes was performed. Under certain conditions, P-EG-based ion-selective electrodes (ISEs) containing TFPB and plasticized with NPOE exhibited a super-Nernstian response between1×10−3and1×10−4 M Cs+, a response characteristic not observed in analogous membranes plasticized with either DOS or FPNPE. Additionally, the performance of P-EG-based ISEs was compared to electrodes based on two mobile ionophores, a neutral lipophilic ethylene glycol derivative (ethylene glycol monooctadecyl ether (U-EG)) and a charged metallacarborane ionophore, sodium bis(dicarbollyl)cobaltate(III) (CC). In general, P-EG-based electrodes plasticized with FPNPE yielded the best performance, with a linear range from 10-1–10-5 M Cs+, a conventional lower detection limit of8.1×10−6 M Cs+, and a response slope of 57.7 mV/decade. The pH response of P-EG ISEs containing TFPB was evaluated for membranes plasticized with either NPOE or FPNPE. In both cases, the electrodes remained stable throughout the pH range 3–12, with only slight proton interference observed below pH 3.
Collapse
Affiliation(s)
- Shane Peper
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
- Radiochemical Analysis Group, Chemical & Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Chad Gonczy
- Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| |
Collapse
|
13
|
Chernyshov DV, Egorov VM, Shvedene NV, Pletnev IV. Low-melting ionic solids: versatile materials for ion-sensing devices. ACS APPLIED MATERIALS & INTERFACES 2009; 1:2055-2059. [PMID: 20355832 DOI: 10.1021/am9004072] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Ionic liquids that melt slightly above room temperature (and may be called low-melting ionic solids, LMISs) were used as sensing materials for the detection of ions in aqueous solutions. A simple procedure based on the consecutive melting and further solidification of the LMISs was applied to prepare solid-contact ion-sensitive electrodes. A potentiometric response toward a number of anions was observed, and the possibility of altering the selectivity by incorporating additional ionophores into the LMIS matrix was demonstrated.
Collapse
Affiliation(s)
- Denis V Chernyshov
- Department of Chemistry, M. V. Lomonosov Moscow State University, 119991 Moscow, Russia
| | | | | | | |
Collapse
|
14
|
Faridbod F, Norouzi P, Dinarvand R, Ganjali MR. Developments in the Field of Conducting and Non-conducting Polymer Based Potentiometric Membrane Sensors for Ions Over the Past Decade. SENSORS (BASEL, SWITZERLAND) 2008; 8:2331-2412. [PMID: 27879825 PMCID: PMC3673421 DOI: 10.3390/s8042331] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Accepted: 04/02/2008] [Indexed: 12/07/2022]
Abstract
Many research studies have been conducted on the use of conjugated polymers in the construction of chemical sensors including potentiometric, conductometric and amperometric sensors or biosensors over the last decade. The induction of conductivity on conjugated polymers by treating them with suitable oxidizing agents won Heeger, MacDiarmid and Shirakawa the 2000 Nobel Prize in Chemistry. Common conjugated polymers are poly(acetylene)s, poly(pyrrole)s, poly(thiophene)s, poly(terthiophene)s, poly(aniline)s, poly(fluorine)s, poly(3-alkylthiophene)s, polytetrathiafulvalenes, polynapthalenes, poly(p-phenylene sulfide), poly(p-phenylenevinylene)s, poly(3,4-ethylenedioxythiophene), polyparaphenylene, polyazulene, polyparaphenylene sulfide, polycarbazole and polydiaminonaphthalene. More than 60 sensors for inorganic cations and anions with different characteristics based on conducting polymers have been reported. There have also been reports on the application of non-conducting polymers (nCPs), i.e. PVC, in the construction of potentiometric membrane sensors for determination of more than 60 inorganic cations and anions. However, the leakage of ionophores from the membranes based on these polymers leads to relatively lower life times. In this article, we try to give an overview of Solid-Contact ISE (SCISE), Single-Piece ISE (SPISE), Conducting Polymer (CP)-Based, and also non-conducting polymer PVC-based ISEs for various ions which their difference is in the way of the polymer used with selective membrane. In SCISEs and SPISEs, the plasticized PVC containing the ionophore and ionic additives govern the selectivity behavior of the electrode and the conducting polymer is responsible of ion-to-electron transducer. However, in CPISEs, the conducting polymer layer is doped with a suitable ionophore which enhances the ion selectivity of the CP while its redox response has to be suppressed.
Collapse
Affiliation(s)
- Farnoush Faridbod
- Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran, Iran
| | - Parviz Norouzi
- Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran, Iran
| | - Rassoul Dinarvand
- Medical Nanotechnology Research Centre, Medical Sciences/University of Tehran, Tehran, P.O. Box 14155-6451, Iran
| | - Mohammad Reza Ganjali
- Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran, Iran.
| |
Collapse
|
15
|
Wang L, Meyerhoff ME. Polymethacrylate polymers with appended aluminum(III)-tetraphenylporphyrins: Synthesis, characterization and evaluation as macromolecular ionophores for electrochemical and optical fluoride sensors. Anal Chim Acta 2008; 611:97-102. [PMID: 18298973 DOI: 10.1016/j.aca.2008.01.070] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 01/21/2008] [Accepted: 01/26/2008] [Indexed: 11/17/2022]
Abstract
The synthesis and characterization of a novel polymethacylate polymer with covalently linked Al(III)-tetraphenylporphyrin (Al(III)-TPP) groups is reported. The new polymer is examined as a potential macromolecular ionophore for the preparation of polymeric membrane-based potentiometric and optical fluoride selective sensors. To prepare the polymer, an Al(III) porphyrin monomer modified with a methacrylate functionality is synthesized, allowing insertion into a polymethacrylate block copolymer (methyl methacrylate and decyl methacrylate) backbone. The resulting polymer can then be incorporated, along with appropriate additives, into conventional plasticized poly(vinyl chloride) films for testing electrochemical and optical fluoride response properties. The covalent attachment of the Al(III)-TPP ionophore to the copolymer matrix provides potentiometric sensors that exhibit significant selectivity for fluoride ion with extended lifetimes (compared to ion-selective membrane electrodes formulated with conventional free Al(III)-TPP structure). However, quite surprisingly, the attachment of the ionophore to the polymer does not eliminate the interaction of Al(III)-TPP structures to form dimeric species within the membrane phase in the presence of fluoride ion. Such interactions are confirmed by UV/visible spectroscopy of the blended polymeric films. Use of the new polymer-Al(III)-TPP conjugates to prepare optical fluoride sensors by co-incorporating a lipophilic pH indicator (4',5'-dibromofluorescein octadecyl ester; ETH7075) is also examined and the resulting optical sensing films are shown to exhibit excellent selectivity for fluoride, with the potential for prolonged operational lifetime.
Collapse
Affiliation(s)
- Lin Wang
- University of Michigan, Department of Chemistry, 930 N. University, Ann Arbor, MI 48109-1055, USA
| | | |
Collapse
|
16
|
Affiliation(s)
- Johan Bobacka
- Åbo Akademi University, Process Chemistry Centre, c/o Laboratory of Analytical Chemistry, Biskopsgatan 8, FI-20500 Turku-Åbo, Finland; Faculty of Material Science and Ceramics, AGH-University of Science and Technology, Al. Mickiewicza 30, PL-30059 Cracow, Poland; and Åbo Akademi University, Process Chemistry Centre, c/o Center for Process Analytical Chemistry and Sensor Technology (ProSens), Biskopsgatan 8, FI-20500 Turku-Åbo, Finland
| | - Ari Ivaska
- Åbo Akademi University, Process Chemistry Centre, c/o Laboratory of Analytical Chemistry, Biskopsgatan 8, FI-20500 Turku-Åbo, Finland; Faculty of Material Science and Ceramics, AGH-University of Science and Technology, Al. Mickiewicza 30, PL-30059 Cracow, Poland; and Åbo Akademi University, Process Chemistry Centre, c/o Center for Process Analytical Chemistry and Sensor Technology (ProSens), Biskopsgatan 8, FI-20500 Turku-Åbo, Finland
| | - Andrzej Lewenstam
- Åbo Akademi University, Process Chemistry Centre, c/o Laboratory of Analytical Chemistry, Biskopsgatan 8, FI-20500 Turku-Åbo, Finland; Faculty of Material Science and Ceramics, AGH-University of Science and Technology, Al. Mickiewicza 30, PL-30059 Cracow, Poland; and Åbo Akademi University, Process Chemistry Centre, c/o Center for Process Analytical Chemistry and Sensor Technology (ProSens), Biskopsgatan 8, FI-20500 Turku-Åbo, Finland
| |
Collapse
|
17
|
Radu A, Peper S, Bakker E, Diamond D. Guidelines for Improving the Lower Detection Limit of Ion-Selective Electrodes: A Systematic Approach. ELECTROANAL 2007. [DOI: 10.1002/elan.200603741] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
18
|
|
19
|
Szigeti Z, Vigassy T, Bakker E, Pretsch E. Approaches to Improving the Lower Detection Limit of Polymeric Membrane Ion-Selective Electrodes. ELECTROANAL 2006; 18:1254-1265. [PMID: 20336172 PMCID: PMC2844646 DOI: 10.1002/elan.200603539] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2006] [Accepted: 04/03/2006] [Indexed: 11/10/2022]
Abstract
More than ten different approaches for improving the lower detection limit of polymeric membrane ion-selective electrodes have been suggested during the recent years. In this contribution, their principles are briefly summarized with a focus to their general practical applicability. The methods that are the most rugged and the easiest to implement in a routine laboratory will be highlighted.
Collapse
Affiliation(s)
- Zsófia Szigeti
- Laboratorium für Organische Chemie, ETH-Hönggerberg, HCI E313, CH-8093 Zürich, Switzerland
| | - Tamás Vigassy
- Laboratorium für Organische Chemie, ETH-Hönggerberg, HCI E313, CH-8093 Zürich, Switzerland
| | - Eric Bakker
- Department of Chemistry, 560 Oval Drive, Purdue University, West Lafayette, IN 47907, USA
| | - Ernö Pretsch
- Laboratorium für Organische Chemie, ETH-Hönggerberg, HCI E313, CH-8093 Zürich, Switzerland
| |
Collapse
|
20
|
Qin Y, Bakker E. Elimination of dimer formation in InIIIporphyrin-based anion-selective membranes by covalent attachment of the ionophore. Anal Chem 2006; 76:4379-86. [PMID: 15283576 DOI: 10.1021/ac049577f] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The spontaneous hydroxy-bridged dimer formation of metalloporphyrins in ion-selective membranes gives rise to a short sensor lifetime (typically days), triggered by solubility problems, the occurrence of a super-Nernstian response slope, and a pH cross response. This dimer formation is eliminated here by covalent attachment of the ionophore to the polymer matrix. Specifically, two different indium(III)porphyrins containing polymerizable groups, the chloride-selective chloro(3-[18-(3-acryloyloxypropyl)-7,12-bis(1-methoxyethyl)-3,8,13,17-tetramethylporphyrin-2-yl]propyl ester)indium(III) and the nitrite-selective Chloro(5-(4-acryloyloxyphenyl)-10,15,20-triphenylporphyrinato)indium(III), were synthesized and copolymerized with methyl methacrylate and decyl methacrylate. The covalent attachment of the ionophore to the polymer matrix indeed prevents the metalloporphyrin from forming dimeric species, as confirmed by UV/visible spectroscopy. The ion-selective membranes with grafted indium porphyrin showed Nernstian response slopes to chloride, nitrite, perchlorate, and thiocyanate anions, with a selectivity comparable to membranes with freely dissolved or underivatized metalloporphyrin. The membranes containing grafted ionophores showed a lifetime of at least two months, apparently since crystallization of the poorly soluble dimeric species may no longer occur. This is one of the first examples where the covalent attachment of an ionophore drastically improves on a number of important sensor characteristics.
Collapse
Affiliation(s)
- Yu Qin
- Department of Chemistry, Auburn University, Auburn, Alabama 36849, USA
| | | |
Collapse
|
21
|
|
22
|
Ruedas-Rama MJ, Hall EAH. K+-selective nanospheres: maximising response range and minimising response time. Analyst 2006; 131:1282-91. [PMID: 17124535 DOI: 10.1039/b608901a] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cross-linked K(+) ion-selective copolymer nanospheres have been prepared by free-radical photo-initiated polymerization of n-butyl acrylate (nBA) with hexanedioldiacrylate (HDDA). Nanospheres (<200 nm) containing H(+)-chromoionophore (ETH 5294) and lipophilic salt (KTClPB) for H(+)-sensors, or ETH 5294, a K(+)-selective ionophore (valinomycin) and anionic sites for K(+)-sensors were compared, and the effect of varying the normalised concentrations for beta (R(T)(-)/L(T)) and gamma (C(m)(T)/L(T)) was studied. Experimental data were fitted to theoretical curves for the dynamic response range, based on the effect of changes in the concentration of these lipophilic sensing components incorporated into the spheres, and conditions identified for maximising the response range. A complex valinomycin-K(+) formation constant, log K(IL) = 13.13 +/- 2.22, was obtained in the nBA matrix, and from the calibration curves the apparent acid-dissociation equilibrium constant (pK(a) = 12.92 +/- 0.03) was extracted for the H(+)-sensing system, and the equilibrium exchange constant (pK(exch) = 6.16 +/- 0.03, at pH 7) calculated for the K(+)-sensing nanospheres. A basis for establishing optimum performance was identified, whereby response range and response time were balanced with maximum fluorescence yield. Parameters for achieving nanospheres with a response time <5 minutes, covering 2-3 orders of magnitude change in activity were identified, demanding nanospheres with radius <300 nm and beta(crit) approximately 0.6. An RSD(%) approximately 3% was obtained in a study of the reproducibility of the response of the proposed nanospheres, and selectivity was also evaluated for a K(+)-selective nanosensor using several cations as interfering agents. In most cases, the fluorescent emission spectra showed no response to the cations tested, confirming the selectivity of nanospheres to potassium ion. The nanosensors were satisfactorily applied to the determination of K(+) in samples mimicking physiological conditions.
Collapse
|
23
|
|
24
|
Langmaier J, Lindner E. Detrimental changes in the composition of hydrogen ion-selective electrode and optode membranes. Anal Chim Acta 2005. [DOI: 10.1016/j.aca.2005.04.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
25
|
Püntener M, Vigassy T, Baier E, Ceresa A, Pretsch E. Improving the lower detection limit of potentiometric sensors by covalently binding the ionophore to a polymer backbone. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2003.10.030] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
26
|
Abstract
BLM prepared on electrode substrates by supporting or tethering were tested for 'pin-hole' character, comparing data from cyclic voltammetry (CV), surface plasmon resonance (SPR) and rotating disc electrodes (RDE). 1-hexadecylamine tethered BLMs on SAM modified gold electrodes were compared with BLMs assembled on modified polyHEMA or sol-gel layers. BLM formation followed by SPR showed that the initial phase of the assembly was complete in 5-20 minutes and produced layers of thickness >5 nm, compared with the expected final BLM thickness of approximately 3 nm. The CVs of the K(3)[Fe(CN)(6)] couple were significantly suppressed irrespective of the method of BLM assembly, without major differences emerging for the different methods. However, data from the RDE distinguished the 'pin-hole' character of the different preparations. The data were consistent with incomplete initial (<1 h, SPR estimated BLM thickness >5 nm) vesicle fusion leaving 'pin-holes' of approximately 2 microm (HDA-11-mercaptoundecanoic acid (MUA) tethered BLM) to approximately 3 microm (tetraethylorthosilicate sol-gel supported BLM) followed by a slow maturation (>15 h; impedance spectroscopy estimated thickness approximately 3 nm) and lateral spreading and fusion, resulting in loss of 'pin-hole' character (<1 microm). The BLM could be used in conjunction with potentiometric measurement to observe the incorporation of nystatin into the BLM and the rate of incorporation adjusted according to original permeability of the BLM. The 'pin-hole-free' BLM construction with lowest permeability (TEOS supported, 4 x 10(-10) cm s(-1) compared with HDA-MUA, 3 x 10(-9) cm s(-1)) gave a potentiometric signal independent of bulk ion-concentration across 5 decades change in concentration. Formed on an ion-selective electrode, nystatin incorporation could be followed as a change in potential, over >2 h, whereas the TEOS supported BLM with permeability 1 x 10(-9) cm s(-1) shows nystatin incorporation within 1 h. In this instance, addition of ConA reduced the potential to the same value as prior to nystatin incorporation, consistent with nystatin channel closure.
Collapse
Affiliation(s)
- Marian Rehak
- Institute of Biotechnology, University of Cambridge, Cambridge CB2 1QT, UK
| | | |
Collapse
|
27
|
Plasticizer-free microspheres for ionophore-based sensing and extraction based on a methyl methacrylate-decyl methacrylate copolymer matrix. Anal Chim Acta 2003. [DOI: 10.1016/s0003-2670(03)00275-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
28
|
Qin Y, Bakker E. A Copolymerized Dodecacarborane Anion as Covalently Attached Cation Exchanger in Ion-Selective Sensors. Anal Chem 2003; 75:6002-10. [PMID: 14588043 DOI: 10.1021/ac034447c] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The traditional cation exchangers used in ion-selective electrodes and optodes are tetraphenylborate derivatives, which are generally adequate for most analytical applications but may in some cases suffer from decomposition by acid hydrolysis, oxidants, and light. Recently, halogenated dodecacarboranes were found to be improved cation exchangers in terms of lipophilicity and chemical stability. This forms the basis for the convenient covalent attachment of the cation exchanger to the polymeric backbone of the sensing material. This is a challenge that has not satisfactorily been solved and which is especially important in view of developing ultraminiaturized sensing arrays. Here, a C-derivative of the closo-dodecacarborane anion (CB(11)H(12)(-)) with a polymerizable group was synthesized as a chemically stable cation exchanger. This new derivative was copolymerized with methyl methacrylate and decyl methacrylate (MMA-DMA) to fabricate a plasticizer-free polymer with cation-exchange properties. This polymer could be conveniently blended with traditional plasticized poly(vinyl chloride) or with noncrosslinked methacrylic polymers to give solvent cast films that appear to be clear and homogeneous and that could be doped with ionophores. Optode leaching experiments supported the covalent grafting of the carborane anions. Ion-selective membranes and optode thin films were evaluated in terms of response function, response time, and selectivity. In all cases, the new material exhibited behavior similar to free tetraphenylborate derivative-based membranes. As a result of these studies, an all-polymeric plasticizer-free calcium-selective membrane was fabricated on the basis of the covalently attached carborane, a recently introduced grafted calcium ionophore, and an MMA-DMA polymer matrix. The resulting ion-selective electrodes showed Nernstian response slopes and rapid response times, demonstrating that covalent grafting of all sensing components is a feasible approach to the development of ion sensors.
Collapse
Affiliation(s)
- Yu Qin
- Department of Chemistry, Auburn University, Auburn, Alabama 36849, USA
| | | |
Collapse
|
29
|
Qin Y, Peper S, Radu A, Ceresa A, Bakker E. Plasticizer-free polymer containing a covalently immobilized Ca2+-selective ionophore for potentiometric and optical sensors. Anal Chem 2003; 75:3038-45. [PMID: 12964748 DOI: 10.1021/ac0263059] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A derivative of a known Ca2+-selective ionophore, ETH 129, was synthesized to contain a polymerizable acrylic moiety (AU-1) and covalently grafted into a methyl methacrylate-co-decyl methacrylate polymer matrix. The polymer containing AU-1 was prepared via a simple one-step homogeneous polymerization method. It exhibited mechanical properties suitable for the fabrication of plasticizer-free ion-selective membrane electrodes and bulk optode films by solvent-casting and spin-coating techniques, respectively. The segmented sandwich membrane technique was utilized to assess the binding constant of free and covalently bound ionophores to calcium and to study their diffusion coefficients in the membrane phase. Diffusion was greatly diminished for the bound ionophore. This was confirmed in ion-selective electrode membranes containing no calcium ions in the inner solution, which should normally show apparent super-Nernstian response slopes in dilute calcium solutions. The response slope was Nernstian down to submicromolar concentration levels, indicating slow mass transport of calcium in the membrane. Optical-sensing films with the new copolymer matrix, unblended and blended with PVC-DOS, also confirmed that covalently bound ionophores are fully functional for maintaining selective ion extraction and binding properties of the sensing membrane.
Collapse
Affiliation(s)
- Yu Qin
- Department of Chemistry, Auburn University, Auburn, Alabama 36849, USA
| | | | | | | | | |
Collapse
|
30
|
Influence of Methacrylic-Acrylic Copolymer Composition on Plasticiser-free Optode Films for pH Sensors. SENSORS 2003. [DOI: 10.3390/s30400083] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
31
|
A Hydrogen Ion-Selective Sensor Based on Non-Plasticised Methacrylic-acrylic Membranes. SENSORS 2002. [DOI: 10.3390/s20800339] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
32
|
Affiliation(s)
- Eric Bakker
- Department of Chemistry, Auburn University, Alabama 36849, USA
| | | |
Collapse
|
33
|
Cross-linked dodecyl acrylate microspheres: novel matrices for plasticizer-free optical ion sensing. Anal Chim Acta 2001. [DOI: 10.1016/s0003-2670(01)01132-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|