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van den Broek J, Keller SD, Goodall I, Parish-Virtue K, Bauer-Christoph C, Fuchs J, Tsipi D, Güntner AT, Blum T, Mathurin JC, Steiger MG, Shirvani R, Gössinger M, Graf M, Anderhub P, Z'graggen D, Hüsser C, Faigle B, Agapios A. Handheld methanol detector for beverage analysis: interlaboratory validation. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2024; 16:3859-3866. [PMID: 38847307 DOI: 10.1039/d4ay00919c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Methanol is a toxic alcohol contained in alcoholic beverages as a natural byproduct of fermentation or added intentionally to counterfeits to increase profit. To ensure consumer safety, many countries and the EU have established strict legislation limits for methanol content. Methanol concentration is mostly detected by laboratory instrumentation since mobile devices for routine on-site testing of beverages in distilleries, at border stations or even at home are not available. Here, we validated a handheld methanol detector for beverage analysis in an ISO 5725 interlaboratory trial: a total of 119 measurements were performed by 17 independent participants (distilleries, universities, authorities, and competence centers) from six countries on samples with relevant methanol concentrations (0.1, 1.5 vol%). The detector was based on a microporous separation filter and a nanostructured gas sensor allowing on-site measurement of methanol down to 0.01 vol% (in the liquid) within only 2 min by laymen. The detector showed excellent repeatability (<5.4%), reproducibility (<9.5%) and small bias (<0.012 vol%). Additional measurements on various methanol-spiked alcoholic beverages (whisky, rum, gin, vodka, tequila, port, sherry, liqueur) indicated that the detector is not interfered by environmental temperature and spirit composition, featuring excellent linearity (R2 > 0.99) down to methanol concentrations of 0.01 vol%. This device has been recently commercialized (Alivion Spark M-20) with comparable accuracy to the gold-standard gas chromatography and can be readily applied for final product inspection, intake control of raw materials or to identify toxic counterfeit products.
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Affiliation(s)
| | | | - Ian Goodall
- Scotch Whisky Research Institute, UK-EH144AP Riccarton, UK
| | | | | | - Johannes Fuchs
- Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, DE-97082 Würzburg, Germany
| | - Despina Tsipi
- General Chemical State Laboratory, GR-11521 Athens, Greece
| | - Andreas T Güntner
- Human-centered Sensing Laboratory, ETH Zürich, CH-8092 Zürich, Switzerland
| | - Thomas Blum
- Research Division Food Microbial Systems, Agroscope, CH-8820 Wädenswil, Switzerland
| | | | - Matthias G Steiger
- Institute of Chemical, Environmental and Bioscience Engineering, Research Group Biochemistry, TU Wien, AT-1060 Vienna, Austria
| | - Roghayeh Shirvani
- Institute of Chemical, Environmental and Bioscience Engineering, Research Group Biochemistry, TU Wien, AT-1060 Vienna, Austria
| | - Manfred Gössinger
- Department of Fruit Processing, Federal College and Research Institute for Viticulture and Pomology Klosterneuburg, AT-3400 Klosterneuburg, Austria
| | - Monika Graf
- Department of Fruit Processing, Federal College and Research Institute for Viticulture and Pomology Klosterneuburg, AT-3400 Klosterneuburg, Austria
| | | | | | | | | | - Agapiou Agapios
- Department of Chemistry, University of Cyprus, CY-1678 Nicosia, Cyprus
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Singh BP, Hwang SJ. Unveiling the potential of polymer cholesteric liquid crystal interpenetrating networks as a label-free alcohol biochemical sensor. Analyst 2024; 149:3456-3467. [PMID: 38738996 DOI: 10.1039/d4an00464g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
In this study, an optical sensor is developed, incorporating hydrogen-bonded photonic array dots containing poly(acrylic acid) (PAA) within a polymer cholesteric liquid crystal interpenetrating polymer network (PCLCIPN) framework, thereby effectively controlling porosity. This methodology involves the fabrication of a porous photonic film, subsequent infusion with a hydrogel (PAA), and precise UV-curing to generate patterned array dots. The sensor exhibits exceptional discriminatory capability between methanol and ethanol, accurately discerning their varying concentrations within alcohol solutions. The optical sensing performance of the film is rigorously evaluated through continuous monitoring of wavelength shifts in the transmission spectrum across various alcohol concentrations. Notably, the observed wavelength shifts demonstrate a linear correlation with the concentration of alcohol, thereby enabling precise quantitative analysis of the alcohol solutions. The sensor exhibits a sensitivity of 0.44 nm/% for ethanol concentrations ranging from 5% to 60%, increasing to 2.1 nm/% for concentrations between 60% and 80%. Similarly, for methanol, sensitivities of 0.68 nm/% (5-60%) and 2.2 nm/% (60-80%) are recorded. Remarkably, this sensitivity trend extends seamlessly to 1 : 1 ethanol/methanol ratios, with values of 0.49 nm/% (5-60%) and 2.25 nm/% (60-80%). Furthermore, these sensors demonstrate colorimetric response to different alcohols, rendering them accessible and cost-effective biosensors for visual detection, thus obviating the necessity for complex analytical instruments.
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Affiliation(s)
- Bhupendra Pratap Singh
- Department of Electro-Optical Engineering, National United University, Miao-Li 360, Taiwan.
| | - Shug-June Hwang
- Department of Electro-Optical Engineering, National United University, Miao-Li 360, Taiwan.
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Hussain S, Zourob M. Solid-State Cholesteric Liquid Crystals as an Emerging Platform for the Development of Optical Photonic Sensors. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2304590. [PMID: 37800619 DOI: 10.1002/smll.202304590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/25/2023] [Indexed: 10/07/2023]
Abstract
Over the past decade, solid-state cholesteric liquid crystals (CLCsolid ) have emerged as a promising photonic material, heralding new opportunities for the advancement of optical photonic biosensors and actuators. The periodic helical structure of CLCsolid s gives rise to their distinctive capability of selectively reflecting incident radiation, rendering them highly promising contenders for a wide spectrum of photonic applications. Extensive research is conducted on utilizing CLCsolid 's optical characteristics to create optical sensors for bioassays, diagnostics, and environmental monitoring. This review provides an overview of emerging technologies in the field of interpenetrating polymeric network-CLCsolid (IPN) and CLCsolid -based optical sensors, including their structural designs, processing, essential materials, working principles, and fabrication methodologies. The review concludes with a forward-looking perspective, addressing current challenges and potential trajectories for future research.
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Affiliation(s)
- Saddam Hussain
- Department of Chemistry, College of Science, Alfaisal University, Al-Maather, Riyadh, 11533, Saudi Arabia
| | - Mohammed Zourob
- Department of Chemistry, College of Science, Alfaisal University, Al-Maather, Riyadh, 11533, Saudi Arabia
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Li Y, Yin Z, Luo D. Pre-compressed polymer cholesteric liquid crystal based optical fiber VOC sensor with high stability and a wide detection range. OPTICS EXPRESS 2022; 30:32822-32832. [PMID: 36242336 DOI: 10.1364/oe.470518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 08/12/2022] [Indexed: 06/16/2023]
Abstract
As the concentration of VOC gases is very high in organic chemical reactions, in order to ensure the safety and accuracy of the experiment, it is very important to develop a gas sensor with a wide detection range. Exploring the mechanism and law of photonic bandgap (PBG) shift after absorption of volatile organic compounds (VOCs) vapors are two basic premises of resolving the PCLC for gas detection with a wide measurement range and stability. Herein, the PCLC films doped with different concentrations of polymer are used for acetone vapor detection, and the shift law of the PBG position is analyzed. As the increase of the detected gas concentration, the intractable problem is that the PBG position of PCLC exhibits red- and blue-shifts successively. Particularly, the pre-compressed technique is highly important for development of a high-performance PCLC based fiber probe, which is crucial for effectively solving the bottleneck problem mentioned. It enables detection of a wide range of acetone vapor concentration from 0 ppm to 50×104 ppm, and the corresponding mean sensitivity of 0.23 pm/ppm. In addition, the thermal crosstalk is generally negligible at temperature below 40°C. Therefore, it is a breakthrough that the described technique not only effectively enhances the stability and robustness of the PCLC fiber probe for VOC vapor detection, but also improves its sensitivity and detection range. The pre-compressed technique provides a novel avenue for fabrication of other PCLC-based devices.
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