Optical Chemical Sensors and Spectroscopy

A special issue of Chemosensors (ISSN 2227-9040). This special issue belongs to the section "Optical Chemical Sensors".

Deadline for manuscript submissions: closed (30 November 2022) | Viewed by 22141

Special Issue Editors


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Guest Editor
International Frequency Sensor Association (IFSA), 08860 Castelldefels, Spain
Interests: smart sensors; optical sensors; frequency measurements
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Graduate Institute of Biomedical Engineering, National Chung-Hsing University, Taichung 40227, Taiwan
Interests: chemical sensors; biosensors; immunosensors; nanomaterials
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The field of optical chemical sensors has been a growing research area over the last decades, finding increasing application in industry, environment, monitoring, medicine, biomedicine, and chemical analysis. The recent developments in this area are driven by such factors as the availability of low-cost, miniature optoelectronic light sources and frequency-output detectors, the need for multianalyte array-based sensors (particularly in the area of biosensing), advances in microfluidics and imaging technology, and the trend toward sensor networks.  

This Special Issue “Optical Chemical Sensors and Spectroscopy” will include extended papers from both annual IFSA conferences, 7th International Conference on Sensors and Electronic Instrumentation Advances (SEIA' 2021) and 4th International Conference on Optics, Photonics and Lasers (OPAL' 2021), but we also strongly encourage researchers unable to participate in the conferences to submit articles for this call. Authors of selected high-quality papers from the conference will be invited to submit extended versions of their original papers (50% extensions of the contents of the conference paper) and other contributions.

Topics of interest for submission include, but are not limited to, the following:

  • Optical chemical sensors;
  • Optical transduction;
  • Spectroscopic sensing;
  • Imaging;
  • Optical absorption;
  • Luminescence-based sensors;
  • Fluorescence-based sensors;
  • Interferometric sensors;
  • Fiber-optic sensor platforms;
  • Diode laser sensing systems;
  • Sol–gel-materials-based sensors.

These topics directly fit the scope of MDPI’s open access journal Chemosensors.

Dr. Sergey Y. Yurish
Prof. Dr. Gou-Jen Wang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Chemosensors is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • optical chemical sensors
  • optical transduction
  • spectroscopy
  • imaging

Published Papers (9 papers)

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Research

8 pages, 2116 KiB  
Communication
Highly Sensitive Plasmonic Sensor with Au Bow Tie Nanoantennas on SiO2 Nanopillar Arrays
by Priyamvada Venugopalan and Sunil Kumar
Chemosensors 2023, 11(2), 121; https://doi.org/10.3390/chemosensors11020121 - 7 Feb 2023
Cited by 7 | Viewed by 1633
Abstract
We report on plasmonic sensors based on arrays of metallic bow tie nanoantennas with high sensitivity and an enhanced figure of merit. In the present sensing device, each gold nanoantenna is positioned on the upper surface of a SiO2 nanopillar that is [...] Read more.
We report on plasmonic sensors based on arrays of metallic bow tie nanoantennas with high sensitivity and an enhanced figure of merit. In the present sensing device, each gold nanoantenna is positioned on the upper surface of a SiO2 nanopillar that is placed on a quartz substrate. The presence of the nanopillar significantly reduces the coupling of the enhanced electromagnetic field generated at the plasmon resonance to the substrate. The simulated results show that the sensitivity of the device to refractive index sensing is 612 nm/RIU, calculated by the resonance wavelength shift per refractive index unit due to the change in the ambient medium index, while the full width at half maximum is calculated at around 10 nm with a figure of merit of 61. The proposed sensor thus has a great potential for sensing and detection applications. Full article
(This article belongs to the Special Issue Optical Chemical Sensors and Spectroscopy)
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22 pages, 2060 KiB  
Article
Polarity-Dependent Twisted Intramolecular Charge Transfer in Diethylamino Coumarin Revealed by Ultrafast Spectroscopy
by Jiawei Liu, Cheng Chen and Chong Fang
Chemosensors 2022, 10(10), 411; https://doi.org/10.3390/chemosensors10100411 - 11 Oct 2022
Cited by 10 | Viewed by 2585
Abstract
Twisting intramolecular charge transfer (TICT) is a common nonradiative relaxation pathway for a molecule with a flexible substituent, effectively reducing the fluorescence quantum yield (FQY) by swift twisting motions. In this work, we investigate coumarin 481 (C481) that contains a diethylamino group in [...] Read more.
Twisting intramolecular charge transfer (TICT) is a common nonradiative relaxation pathway for a molecule with a flexible substituent, effectively reducing the fluorescence quantum yield (FQY) by swift twisting motions. In this work, we investigate coumarin 481 (C481) that contains a diethylamino group in solution by femtosecond transient absorption (fs-TA), femtosecond stimulated Raman spectroscopy (FSRS), and theoretical calculations, aided by coumarin 153 with conformational locking of the alkyl arms as a control sample. In different solvents with decreasing polarity, the transition energy barrier between the fluorescent state and TICT state increases, leading to an increase of the FQY. Correlating the fluorescence decay time constant with solvent polarity and viscosity parameters, the multivariable linear regression analysis indicates that the chromophore’s nonradiative relaxation pathway is affected by both hydrogen (H)-bond donating and accepting capabilities as well as dipolarity of the solvent. Results from the ground- and excited-state FSRS shed important light on structural dynamics of C481 undergoing prompt light-induced intramolecular charge transfer from the diethylamino group toward –C=O and –CF3 groups, while the excited-state C=O stretch marker band tracks initial solvation and vibrational cooling dynamics in aprotic and protic solvents (regardless of polarity) as well as H-bonding dynamics in the fluorescent state for C481 in high-polarity protic solvents like methanol. The uncovered mechanistic insights into the molecular origin for the fluorogenicity of C481 as an environment-polarity sensor substantiate the generality of ultrafast TICT state formation of flexible molecules in solution, and the site-dependent substituent(s) as an effective route to modulate the fluorescence properties for such compact, engineerable, and versatile chemosensors. Full article
(This article belongs to the Special Issue Optical Chemical Sensors and Spectroscopy)
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17 pages, 5932 KiB  
Article
Characterisation of Channel Waveguides Fabricated in an Er3+-Doped Tellurite Glass Using Two Ion Beam Techniques
by István Bányász, Istvan Rajta, Gyula U. L. Nagy, Nguyen Q. Khanh, Vladimír Havránek, Vaclav Vosecek, Miklós Fried, Zoltán Szabó, Miklós Veres, Roman Holomb, László Himics and Éva Tichy-Rács
Chemosensors 2022, 10(8), 337; https://doi.org/10.3390/chemosensors10080337 - 17 Aug 2022
Cited by 3 | Viewed by 1452
Abstract
Two methods were proposed and implemented for the fabrication of channel waveguides in an Er-doped Tellurite glass. In the first method, channel waveguides were fabricated by implanting 1.5 MeV and 3.5 MeV energy N+ ions through a special silicon mask to the [...] Read more.
Two methods were proposed and implemented for the fabrication of channel waveguides in an Er-doped Tellurite glass. In the first method, channel waveguides were fabricated by implanting 1.5 MeV and 3.5 MeV energy N+ ions through a special silicon mask to the glass sample at various fluences. Those waveguides implanted at a fluence of 1.0 × 1016 ions/cm2 operated up to 980 nm, and showed green upconversion of the Erbium ions. In the second method, channel waveguides were directly written in the Er3+: TeO2W2O3 glass using an 11 MeV C4+ ion microbeam with fluences in the range of 1 · 1014–5 · 1016 ions/cm2. The waveguides worked in single mode regime up to the 1540 nm telecom wavelength. Propagation losses were reduced from the 14 dB/cm of the as-irradiated waveguides by stepwise thermal annealing to 1.5 dB/cm at λ = 1400 nm. Full article
(This article belongs to the Special Issue Optical Chemical Sensors and Spectroscopy)
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14 pages, 1291 KiB  
Article
Chemical Identification from Raman Peak Classification Using Fuzzy Logic and Monte Carlo Simulation
by Federico Angelini, Simone Santoro and Francesco Colao
Chemosensors 2022, 10(8), 295; https://doi.org/10.3390/chemosensors10080295 - 27 Jul 2022
Cited by 2 | Viewed by 1613
Abstract
In spite of the wide use of Raman spectroscopy for chemical analysis in different fields, not any automated identification of Raman spectra is universally adopted. However, the interest in this field is witnessed by the large number of papers published in the last [...] Read more.
In spite of the wide use of Raman spectroscopy for chemical analysis in different fields, not any automated identification of Raman spectra is universally adopted. However, the interest in this field is witnessed by the large number of papers published in the last decades. The problem of Raman-spectra classification becomes particularly challenging when low irradiation is requested, either for safety reasons or to avoid target photodegradation. This often leads to spectra characterized by a low signal-to-noise ratio, where methods based on correlation usually fail. For this reason, a method based on peak identification through FMFs is presented, discussed and validated over a large set of samples. In particular, a Monte Carlo simulation has been employed to determine the best parameters of the fuzzy membership functions based on the analysis of performances of the classification procedure. The ROC curves have been analyzed, and AUC and best accuracy are employed as key parameters to evaluate the classification performances on different amounts of ammonium nitrate (from 300 to 1500 μg) and different laser exposure levels (from 3.1 to 250 mJ/cm2). Full article
(This article belongs to the Special Issue Optical Chemical Sensors and Spectroscopy)
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16 pages, 2798 KiB  
Article
Optofluidic Micromachined Platform for Refractive Index Measurement
by Zoran Djinović, Miloš Tomić and Agnes Kocsis
Chemosensors 2022, 10(5), 197; https://doi.org/10.3390/chemosensors10050197 - 23 May 2022
Viewed by 1910
Abstract
We present a combination of micromachined optofluidic platforms equipped with a fiber-optic sensing configuration based on a three-path Mach–Zehnder interferometer (MZI) for simultaneous measurement of the refractive index of liquids and the autocalibration in dynamic regime. The sensing principle is based on the [...] Read more.
We present a combination of micromachined optofluidic platforms equipped with a fiber-optic sensing configuration based on a three-path Mach–Zehnder interferometer (MZI) for simultaneous measurement of the refractive index of liquids and the autocalibration in dynamic regime. The sensing principle is based on the low-coherence interferometry, characterized by a generation of Gaussian enveloped interferograms, for which the position of its maximum depends on the optical path difference (OPD) between the sensing and reference arm of the MZI. When liquid flows through the central microchannel of the optofluidic platform it crosses the light beam between the two optical fibers in the sensing arm causing the OPD change. An algorithm has been applied for the calculation of the refractive index of liquids out of the raw interference signals. We obtained a very good agreement between the experimental results and literature data of refractive indices of subjected fluids. The accuracy of refractive index measurement is approximately 1%, predominantly determined by the accuracy of reading the position of the mechanical scanner. The proposed sensor is attractive for the label-free biological, biochemical, and chemical sensing owing autocalibration and high sensitivity yet consuming a very small sample volume of 1 µL. It is capable to measure the refractive index of various liquids and/or gases simultaneously in the process. Full article
(This article belongs to the Special Issue Optical Chemical Sensors and Spectroscopy)
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14 pages, 2302 KiB  
Article
Photonics of Viburnum opulus L. Extracts in Microemulsions with Oxygen and Gold Nanoparticles
by Anna Tcibulnikova, Evgeniia Zemliakova, Dmitry Artamonov, Vasily Slezhkin, Liubov Skrypnik, Ilia Samusev, Andrey Zyubin, Artemy Khankaev, Valery Bryukhanov and Ivan Lyatun
Chemosensors 2022, 10(4), 130; https://doi.org/10.3390/chemosensors10040130 - 30 Mar 2022
Cited by 1 | Viewed by 1949
Abstract
In this paper, the optical properties of viburnum extract flavonoids in the visible region of the spectrum were investigated and their use as a potential photosensitizer of singlet oxygen for photodynamic therapy was evaluated. The presence of long-lived excited states in the extract [...] Read more.
In this paper, the optical properties of viburnum extract flavonoids in the visible region of the spectrum were investigated and their use as a potential photosensitizer of singlet oxygen for photodynamic therapy was evaluated. The presence of long-lived excited states in the extract molecules was established by spectral methods and time-resolved spectroscopy methods and the dependences of the absorption capacity and luminescence intensity of the extract molecules on the concentrations of oxygen and ablative nanoparticles of the gold in the reverse micelles of AOT (sodium dioctyl sulfosuccinate) were established. The plasmonic enhancement of the luminescence of the extract molecules and the processes of their complexation with oxygen were also established. Furthermore, the rate constants of the processes of conversion of exciting energy in complexes were determined. Full article
(This article belongs to the Special Issue Optical Chemical Sensors and Spectroscopy)
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12 pages, 4128 KiB  
Article
A Comparative Study of Aqueous and Non-Aqueous Solvents to Be Used in Low-Temperature Serial Molecular–Electronic Sensors
by Dmitry Zaitsev, Ivan Egorov and Vadim Agafonov
Chemosensors 2022, 10(3), 111; https://doi.org/10.3390/chemosensors10030111 - 12 Mar 2022
Cited by 5 | Viewed by 2518
Abstract
This paper presents the experimental results of studying the samples of the electrochemical sensors of motion parameters on the base of Molecular Electronics Technology (MET). The sensors with microelectromechanical (MEMS) electrode assembly use electrolytes based on aqueous and non-aqueous solutions of potassium and [...] Read more.
This paper presents the experimental results of studying the samples of the electrochemical sensors of motion parameters on the base of Molecular Electronics Technology (MET). The sensors with microelectromechanical (MEMS) electrode assembly use electrolytes based on aqueous and non-aqueous solutions of potassium and lithium iodides. Electrolyte solutions contain impurities of ionic liquids and alcohols to achieve stable low-temperature operation and acceptable technical parameters of serial devices. The dependence of the general sensitivity and the shape of the amplitude-frequency characteristic on temperature have been studied. For the marginally acceptable samples, which had an acceptable temperature dependence of the conversion coefficient and low activation energies for the diffusion coefficient, the level of self-noise was found. The activation energy of the electrolyte diffusion coefficient was determined based on the analysis of the dependence of the background current on temperature. A conclusion was made regarding the possible prospects for using the studied solutions and components for operation in serial devices. Full article
(This article belongs to the Special Issue Optical Chemical Sensors and Spectroscopy)
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24 pages, 8434 KiB  
Article
Femtosecond Direct Laser Writing of Silver Clusters in Phosphate Glasses for X-ray Spatially-Resolved Dosimetry
by Joelle Harb, Théo Guérineau, Adriana Morana, Arnaud Meyer, Guillaume Raffy, André Del Guerzo, Youcef Ouerdane, Aziz Boukenter, Sylvain Girard, Thierry Cardinal, Yannick Petit and Lionel Canioni
Chemosensors 2022, 10(3), 110; https://doi.org/10.3390/chemosensors10030110 - 11 Mar 2022
Cited by 4 | Viewed by 2803
Abstract
Radio-photoluminescence in silver-doped phosphate glasses has been extensively used for X-ray dosimetry. In this paper, we present the potential of silver clusters for X-ray spatially resolved dosimetry. Those clusters are generated in phosphate glasses containing a high concentration of silver oxide by femtosecond [...] Read more.
Radio-photoluminescence in silver-doped phosphate glasses has been extensively used for X-ray dosimetry. In this paper, we present the potential of silver clusters for X-ray spatially resolved dosimetry. Those clusters are generated in phosphate glasses containing a high concentration of silver oxide by femtosecond direct laser writing technique. Two phosphate glasses of different compositions were investigated. First, the spectroscopic properties of the pristine glasses were studied after X-ray irradiation at different doses to assess their dosimetry potential. Second, the impact of X-rays on the three-dimensional inscribed silver clusters has been analyzed using several spectroscopies methods. Our analysis highlights the resilience of embedded silver clusters acting as local probes of the deposited doses. We demonstrate that these inscribed glasses can define the range and sensitivity of X-ray doses and consider the realization of spatially-resolved dosimeters. Full article
(This article belongs to the Special Issue Optical Chemical Sensors and Spectroscopy)
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13 pages, 3886 KiB  
Article
Cost-Effective Foam-Based Colorimetric Sensor for Roadside Testing of Alcohol in Undiluted Saliva
by Krittapas Kaewnu, Kiattisak Promsuwan, Apichai Phonchai, Adul Thiangchanya, Dongsayam Somapa, Namchoke Somapa, Kunanunt Tayayuth and Warakorn Limbut
Chemosensors 2021, 9(12), 334; https://doi.org/10.3390/chemosensors9120334 - 28 Nov 2021
Cited by 4 | Viewed by 4148
Abstract
A novel foam-based colorimetric alcohol sensor was developed for the detection of alcohol in saliva. Detection was based on the color change of a potassium dichromate-sulfuric acid solution absorbed by melamine foam. In the presence of alcohol, the orange colorimetric sensor changed color [...] Read more.
A novel foam-based colorimetric alcohol sensor was developed for the detection of alcohol in saliva. Detection was based on the color change of a potassium dichromate-sulfuric acid solution absorbed by melamine foam. In the presence of alcohol, the orange colorimetric sensor changed color to brown, green and, ultimately, blue, depending on the concentration of alcohol in the sample. The response of the proposed sensor toward alcohol was linear from 0.10 to 2.5% v/v. The limit of detection was 0.03% v/v. Alcohol concentration could be determined using the naked eye in the range of 0.00 to 10% v/v. The developed alcohol sensor presented good operational accuracy (RSD = 0.30–1.90%, n = 8) and good stability for 21 days when stored at 25 °C and 75 days when stored at 4 °C. The results of alcohol detection with the developed sensor showed no significant difference from the results of spectrophotometric detection at a 95% confidence level (p > 0.05). The sensor was easy to use, small, inexpensive and portable, enabling drivers to accurately measure their own blood alcohol level and providing convenient speed in forensic applications. Full article
(This article belongs to the Special Issue Optical Chemical Sensors and Spectroscopy)
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