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Huffman BL, Bredar ARC, Dempsey JL. Origins of non-ideal behaviour in voltammetric analysis of redox-active monolayers. Nat Rev Chem 2024:10.1038/s41570-024-00629-8. [PMID: 39039210 DOI: 10.1038/s41570-024-00629-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2024] [Indexed: 07/24/2024]
Abstract
Disorder in redox-active monolayers convolutes electrochemical characterization. This disorder can come from pinhole defects, loose packing, heterogeneous distribution of redox-active headgroups, and lateral interactions between immobilized redox-active molecules. Identifying the source of non-ideal behaviour in cyclic voltammograms can be challenging as different types of disorder often cause similar non-ideal cyclic voltammetry behaviour such as peak broadening, large peak-to-peak separation, peak asymmetry and multiple peaks for single redox processes. This Review provides an overview of ideal voltammetric behaviour for redox-active monolayers, common manifestations of disorder on voltammetric responses, common experimental parameters that can be varied to interrogate sources of disorder, and finally, examples of different types of disorder and how they impact electrochemical responses.
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Affiliation(s)
- Brittany L Huffman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Alexandria R C Bredar
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jillian L Dempsey
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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2
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Wu T, Fitchett CM, Brooksby PA, Downard AJ. Building Tailored Interfaces through Covalent Coupling Reactions at Layers Grafted from Aryldiazonium Salts. ACS APPLIED MATERIALS & INTERFACES 2021; 13:11545-11570. [PMID: 33683855 DOI: 10.1021/acsami.0c22387] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Aryldiazonium ions are widely used reagents for surface modification. Attractive aspects of their use include wide substrate compatibility (ranging from plastics to carbons to metals and metal oxides), formation of stable covalent bonding to the substrate, simplicity of modification methods that are compatible with organic and aqueous solvents, and the commercial availability of many aniline precursors with a straightforward conversion to the active reagent. Importantly, the strong bonding of the modifying layer to the surface makes the method ideally suited to further on-surface (postfunctionalization) chemistry. After an initial grafting from a suitable aryldiazonium ion to give an anchor layer, a target species can be coupled to the layer, hugely expanding the range of species that can be immobilized. This strategy has been widely employed to prepare materials for numerous applications including chemical sensors, biosensors, catalysis, optoelectronics, composite materials, and energy conversion and storage. In this Review our goal is first to summarize how a target species with a particular functional group may be covalently coupled to an appropriate anchor layer. We then review applications of the resulting materials.
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Affiliation(s)
- Ting Wu
- School of Physical and Chemical Sciences, University of Canterbury, Christchurch, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Christchurch, New Zealand
| | - Christopher M Fitchett
- School of Physical and Chemical Sciences, University of Canterbury, Christchurch, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Christchurch, New Zealand
| | - Paula A Brooksby
- School of Physical and Chemical Sciences, University of Canterbury, Christchurch, New Zealand
| | - Alison J Downard
- School of Physical and Chemical Sciences, University of Canterbury, Christchurch, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Christchurch, New Zealand
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3
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Nanofabrication Techniques in Large-Area Molecular Electronic Devices. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10176064] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The societal impact of the electronics industry is enormous—not to mention how this industry impinges on the global economy. The foreseen limits of the current technology—technical, economic, and sustainability issues—open the door to the search for successor technologies. In this context, molecular electronics has emerged as a promising candidate that, at least in the short-term, will not likely replace our silicon-based electronics, but improve its performance through a nascent hybrid technology. Such technology will take advantage of both the small dimensions of the molecules and new functionalities resulting from the quantum effects that govern the properties at the molecular scale. An optimization of interface engineering and integration of molecules to form densely integrated individually addressable arrays of molecules are two crucial aspects in the molecular electronics field. These challenges should be met to establish the bridge between organic functional materials and hard electronics required for the incorporation of such hybrid technology in the market. In this review, the most advanced methods for fabricating large-area molecular electronic devices are presented, highlighting their advantages and limitations. Special emphasis is focused on bottom-up methodologies for the fabrication of well-ordered and tightly-packed monolayers onto the bottom electrode, followed by a description of the top-contact deposition methods so far used.
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4
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Delaporte N, Belanger RL, Lajoie G, Trudeau M, Zaghib K. Multi-carbonyl molecules immobilized on high surface area carbon by diazonium chemistry for energy storage applications. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.04.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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5
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Pekarek RT, Celio H, Rose MJ. Synthetic Insights into Surface Functionalization of Si(111)-R Photoelectrodes: Steric Control and Deprotection of Molecular Passivating Layers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:6328-6337. [PMID: 29782175 DOI: 10.1021/acs.langmuir.7b03564] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report the utility of controlled spacing of molecular monolayers on Si(111) surfaces by the use of sterically bulky silanes. The steric bulk of a 3,5-diphenolic linker of type Ph-diO-SiR3 (R = hexyl, phenyl, iPr)-as well as the smaller Ph-diOMe-is shown to control the surface coverage on Si(111). The para substituent was also changed from -F (small) to -OTf (triflate, large) to modulate the conformation of a selected bulky silane (SiR3; R = hexyl) to further control the steric environment of the monolayer. The surface coverage values are found to vary systematically from 57 → 21 → 15 → 11% for the series CH3 → hexyl → iPr → phenyl. Substitution at the para position (F → OTf) decreased the packing density for R = hexyl to as low as 8% (from 21%). The molecular coverage was also found to control the rate and extent of surface oxidation when unfunctionalized sites were allowed to oxidize. Following attachment, facile deprotection of the silanes was achieved by treatment with BBr3 to afford the diphenolic -OH groups. To electronically characterize the monolayers, voltammetry was performed in contact with liquid Hg to determine the barrier height, which was decreased by 70 mV as the coverage is increased. This study provides a synthetic rationale for controlling the packing density of surface linkers using electroless chemistry at semiconductor interfaces, thus providing further tunability and functionality of photoelectrochemical devices.
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Affiliation(s)
- Ryan T Pekarek
- Department of Chemistry , The University of Texas at Austin , Welch Hall, 105 E 24th Street , Austin , Texas 78712 , United States
| | - Hugo Celio
- Department of Chemistry , The University of Texas at Austin , Welch Hall, 105 E 24th Street , Austin , Texas 78712 , United States
| | - Michael J Rose
- Department of Chemistry , The University of Texas at Austin , Welch Hall, 105 E 24th Street , Austin , Texas 78712 , United States
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6
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Bullock RM, Das AK, Appel AM. Surface Immobilization of Molecular Electrocatalysts for Energy Conversion. Chemistry 2017; 23:7626-7641. [PMID: 28178367 DOI: 10.1002/chem.201605066] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 01/29/2017] [Indexed: 12/23/2022]
Abstract
Electrocatalysts are critically important for a secure energy future, as they facilitate the conversion between electrical and chemical energy. Molecular catalysts offer precise control of structure that enables understanding of structure-reactivity relationships, which can be difficult to achieve with heterogeneous catalysts. Molecular electrocatalysts can be immobilized on surfaces by covalent bonds or through non-covalent interactions. Advantages of surface immobilization include the need for less catalyst, avoidance of bimolecular decomposition pathways, and easier determination of catalyst lifetime. This Minireview highlights surface immobilization of molecular electrocatalysts for reduction of O2 , oxidation of H2 O, production of H2 , and reduction of CO2 .
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Affiliation(s)
- R Morris Bullock
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Atanu K Das
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Aaron M Appel
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
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7
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Aryldiazonium salt derived mixed organic layers: From surface chemistry to their applications. J Electroanal Chem (Lausanne) 2017. [DOI: 10.1016/j.jelechem.2016.11.043] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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8
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Breton T, Downard AJ. Controlling Grafting from Aryldiazonium Salts: A Review of Methods for the Preparation of Monolayers. Aust J Chem 2017. [DOI: 10.1071/ch17262] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Surface modification by grafting from aryldiazonium salts has been widely studied and applied to many substrates as a simple and versatile method for preparing strongly adherent organic coatings. Unless special precautions or conditions are used, the usual film structure is a loosely packed disordered multilayer; however, over the past decade, attention has been paid to establishing strategies for grafting just a monolayer of modifiers to the surface. To date, four general approaches to monolayer preparation have emerged: use of aryldiazonium ions with cleavable protection groups; use of aryldiazonium ions with steric constraints; grafting in the presence of a radical scavenger; and grafting from ionic liquids. This review describes these approaches, illustrates some of their applications, and highlights the advantages and disadvantages of each.
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Menanteau T, Dabos-Seignon S, Levillain E, Breton T. Impact of the Diazonium Grafting Control on the Interfacial Reactivity: Monolayer versus Multilayer. ChemElectroChem 2016. [DOI: 10.1002/celc.201600710] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Thibaud Menanteau
- MOLTECH-Anjou; Université d'Angers, UMR CNRS 6200; 2 Boulevard Lavoisier 49045 Angers France
| | - Sylvie Dabos-Seignon
- MOLTECH-Anjou; Université d'Angers, UMR CNRS 6200; 2 Boulevard Lavoisier 49045 Angers France
| | - Eric Levillain
- MOLTECH-Anjou; Université d'Angers, UMR CNRS 6200; 2 Boulevard Lavoisier 49045 Angers France
| | - Tony Breton
- MOLTECH-Anjou; Université d'Angers, UMR CNRS 6200; 2 Boulevard Lavoisier 49045 Angers France
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10
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Lee L, Gunby NR, Crittenden DL, Downard AJ. Multifunctional and Stable Monolayers on Carbon: A Simple and Reliable Method for Backfilling Sparse Layers Grafted from Protected Aryldiazonium Ions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:2626-2637. [PMID: 26918953 DOI: 10.1021/acs.langmuir.5b04546] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A new strategy for preparation of robust multifunctional low nanometer thickness monolayers on carbon substrates is presented. Beginning with protected aryldiazonium salts, sparse monolayers of ethynyl-, amino-, and carboxy-terminated tethers are covalently anchored to the surface. The layers are then backfilled with a second modifier via the nucleophilic addition of an amine derivative to the surface. Through use of electroactive moieties coupled to the tethers, and an electroactive amine for backfilling, electrochemical measurements reveal that backfilling approximately doubles the surface concentration of the monolayer. Cyclic voltammetry of solution-based redox probes at the modified surfaces is consistent with the expected blocking properties at various stages of surface preparation. Fractional surface coverages of the layers are estimated using electrochemically determined surface concentrations of modifiers and computationally derived modifier footprints. Assuming free rotation of the coupled ferrocenyl or nitrophenyl groups leads to physically unreasonable fractional surface coverages, indicating that these larger modifiers must be rotationally restricted. Using a conformationally constrained model produces lower bound estimates of the total fractional surface coverage close to 0.4, with tether-only coverages close to 0.2. The backfilled tether layers constitute practical platforms for controlled construction of complex interfaces with many potential applications including sensing, molecular electronics, and catalysis.
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Affiliation(s)
- Lita Lee
- MacDiarmid Institute for Advanced Materials and Nanotechnology, and ‡Department of Chemistry, University of Canterbury , Private Bag 4800, Christchurch, New Zealand 8140
| | - Nathaniel R Gunby
- MacDiarmid Institute for Advanced Materials and Nanotechnology, and ‡Department of Chemistry, University of Canterbury , Private Bag 4800, Christchurch, New Zealand 8140
| | - Deborah L Crittenden
- MacDiarmid Institute for Advanced Materials and Nanotechnology, and ‡Department of Chemistry, University of Canterbury , Private Bag 4800, Christchurch, New Zealand 8140
| | - Alison J Downard
- MacDiarmid Institute for Advanced Materials and Nanotechnology, and ‡Department of Chemistry, University of Canterbury , Private Bag 4800, Christchurch, New Zealand 8140
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11
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Smith BJ, Hernández Gallegos PA, Butsch K, Stack TDP. Metal complex assembly controlled by surface ligand distribution on mesoporous silica: Quantification using refractive index matching and impact on catalysis. J Catal 2016. [DOI: 10.1016/j.jcat.2015.11.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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12
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Sheridan MV, Lam K, Sharafi M, Schneebeli ST, Geiger WE. Anodic Methods for Covalent Attachment of Ethynylferrocenes to Electrode Surfaces: Comparison of Ethynyl Activation Processes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:1645-1657. [PMID: 26756403 DOI: 10.1021/acs.langmuir.6b00012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The electrochemical oxidation of ferrocenes having an H- or Li-terminated ethynyl group has been studied, especially as it relates to their covalent anchoring to carbon surfaces. The anodic oxidation of lithioethynylferrocene (1-Li) results in rapid loss of Li(+) and formation of the ethynyl-based radical FeCp(η(5)-C5H4)(C≡C), (1, Cp = η(5)-C5H5), which reacts with the electrode. Chemically modified electrodes (CMEs) were thereby produced containing strongly bonded, ethynyl-linked monolayers and electrochemically controlled multilayers. Strong attachments of ethynylferrocenes to gold and platinum surfaces were also possible. The lithiation/anodic oxidation process is a mirror analogue of the diazonium/cathodic reduction process for preparation of aryl-modified CMEs. A second method produced an ethynylferrocene-modified electrode by direct anodic oxidation of the H-terminated ethynylferrocene (1-H) at a considerably more positive potential. Both processes produced robust modified electrodes with well-defined ferrocene-based surface cyclic voltammetry waves that remained unchanged for as many as 10(4) scans. Ferrocene derivatives in which the ethynyl moiety was separated from the cyclopentadienyl ring by an ether group showed very similar behavior. DFT calculations were performed on the relevant redox states of 1-H, 1-Li, and 1, with emphasis on the ferrocenyl vs ethynyl character of their high valence orbitals. Whereas the HOMOs of both 1-H and 1-Li have some ethynyl character, the SOMOs of the corresponding monocations are strictly ferrocenium in makeup. Predominant ethynyl character returns to the highest valence orbitals after loss of Li(+) from [1-Li](+) or loss of H(+) from [1-H](2+). These anodic processes hold promise for the controlled chemical modification of carbon and other electrode surfaces by a variety of ethynyl or alkynyl-linked organic and metal-containing systems.
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Affiliation(s)
- Matthew V Sheridan
- Department of Chemistry, University of Vermont , Burlington, Vermont 05405, United States
| | - Kevin Lam
- Department of Chemistry, University of Vermont , Burlington, Vermont 05405, United States
| | - Mona Sharafi
- Department of Chemistry, University of Vermont , Burlington, Vermont 05405, United States
| | - Severin T Schneebeli
- Department of Chemistry, University of Vermont , Burlington, Vermont 05405, United States
| | - William E Geiger
- Department of Chemistry, University of Vermont , Burlington, Vermont 05405, United States
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13
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Buonaiuto M, De Crisci AG, Jaramillo TF, Waymouth RM. Electrooxidation of Alcohols with Electrode-Supported Transfer Hydrogenation Catalysts. ACS Catal 2015. [DOI: 10.1021/acscatal.5b01830] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Megan Buonaiuto
- Department of Chemistry and ‡Department
of Chemical
Engineering, Stanford University, Stanford, California 94305, United States
| | - Antonio G. De Crisci
- Department of Chemistry and ‡Department
of Chemical
Engineering, Stanford University, Stanford, California 94305, United States
| | - Thomas F. Jaramillo
- Department of Chemistry and ‡Department
of Chemical
Engineering, Stanford University, Stanford, California 94305, United States
| | - Robert M. Waymouth
- Department of Chemistry and ‡Department
of Chemical
Engineering, Stanford University, Stanford, California 94305, United States
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14
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Randriamahazaka H, Ghilane J. Electrografting and Controlled Surface Functionalization of Carbon Based Surfaces for Electroanalysis. ELECTROANAL 2015. [DOI: 10.1002/elan.201500527] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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15
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Chrouda A, Sbartai A, Baraket A, Renaud L, Maaref A, Jaffrezic-Renault N. An aptasensor for ochratoxin A based on grafting of polyethylene glycol on a boron-doped diamond microcell. Anal Biochem 2015; 488:36-44. [PMID: 26255699 DOI: 10.1016/j.ab.2015.07.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 07/19/2015] [Accepted: 07/22/2015] [Indexed: 11/19/2022]
Abstract
A novel strategy for the fabrication of an electrochemical label-free aptasensor for small-size molecules is proposed and demonstrated as an aptasensor for ochratoxin A (OTA). A long spacer chain of polyethylene glycol (PEG) was immobilized on a boron-doped diamond (BDD) microcell via electrochemical oxidation of its terminal amino groups. The amino-aptamer was then covalently linked to the carboxyl end of the immobilized PEG as a two-piece macromolecule, autoassembled at the BDD surface, forming a dense layer. Due to a change in conformation of the aptamer on the target analyte binding, a decrease of the electron transfer rate of the redox [Fe(CN)6](4-/3-) probe was observed. To quantify the amount of OTA, the decrease of the square wave voltammetry (SWV) peak maximum of this probe was monitored. The plot of the peak maximum against the logarithm of OTA concentration was linear along the range from 0.01 to 13.2 ng/L, with a detection limit of 0.01 ng/L. This concept was validated on spiked real samples of rice.
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Affiliation(s)
- A Chrouda
- Laboratory of Interfaces and Advanced Materials, University of Monastir, 5019 Monastir, Tunisia; University of Lyon, Institute of Analytical Sciences, UMR CNRS 5280, 69100 Villeurbanne, France
| | - A Sbartai
- University of Lyon, Institute of Analytical Sciences, UMR CNRS 5280, 69100 Villeurbanne, France
| | - A Baraket
- University of Lyon, Institute of Analytical Sciences, UMR CNRS 5280, 69100 Villeurbanne, France
| | - L Renaud
- University of Lyon, Institute of Nanotechnology of Lyon, UMR CNRS 5270, 69622 Villeurbanne Cedex, France
| | - A Maaref
- Laboratory of Interfaces and Advanced Materials, University of Monastir, 5019 Monastir, Tunisia
| | - N Jaffrezic-Renault
- University of Lyon, Institute of Analytical Sciences, UMR CNRS 5280, 69100 Villeurbanne, France.
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