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Solvent Vapour Detection with Cholesteric Liquid Crystals—Optical and Mass-Sensitive Evaluation of the Sensor Mechanism(†)
Cholesteric liquid crystals (CLCs) are used as sensitive coatings for the detection of organic solvent vapours for both polar and non-polar substances. The incorporation of different analyte vapours in the CLC layers disturbs the pitch length which changes the optical properties, i.e., shifting the...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Molecular Diversity Preservation International (MDPI)
2010
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3292152/ https://www.ncbi.nlm.nih.gov/pubmed/22399912 http://dx.doi.org/10.3390/s100504887 |
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author | Mujahid, Adnan Stathopulos, Helen Lieberzeit, Peter A. Dickert, Franz L. |
author_facet | Mujahid, Adnan Stathopulos, Helen Lieberzeit, Peter A. Dickert, Franz L. |
author_sort | Mujahid, Adnan |
collection | PubMed |
description | Cholesteric liquid crystals (CLCs) are used as sensitive coatings for the detection of organic solvent vapours for both polar and non-polar substances. The incorporation of different analyte vapours in the CLC layers disturbs the pitch length which changes the optical properties, i.e., shifting the absorption band. The engulfing of CLCs around non-polar solvent vapours such as tetrahedrofuran (THF), chloroform and tetrachloroethylene is favoured in comparison to polar ones, i.e., methanol and ethanol. Increasing solvent vapour concentrations shift the absorbance maximum to smaller wavelengths, e.g., as observed for THF. Additionally, CLCs have been coated on acoustic devices such as the quartz crystal microbalance (QCM) to measure the frequency shift of analyte samples at similar concentration levels. The mass effect for tetrachloroethylene was about six times higher than chloroform. Thus, optical response can be correlated with intercalation in accordance to mass detection. The mechanical stability was gained by combining CLCs with imprinted polymers. Therefore, pre-concentration of solvent vapours was performed leading to an additional selectivity. |
format | Online Article Text |
id | pubmed-3292152 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2010 |
publisher | Molecular Diversity Preservation International (MDPI) |
record_format | MEDLINE/PubMed |
spelling | pubmed-32921522012-03-07 Solvent Vapour Detection with Cholesteric Liquid Crystals—Optical and Mass-Sensitive Evaluation of the Sensor Mechanism(†) Mujahid, Adnan Stathopulos, Helen Lieberzeit, Peter A. Dickert, Franz L. Sensors (Basel) Article Cholesteric liquid crystals (CLCs) are used as sensitive coatings for the detection of organic solvent vapours for both polar and non-polar substances. The incorporation of different analyte vapours in the CLC layers disturbs the pitch length which changes the optical properties, i.e., shifting the absorption band. The engulfing of CLCs around non-polar solvent vapours such as tetrahedrofuran (THF), chloroform and tetrachloroethylene is favoured in comparison to polar ones, i.e., methanol and ethanol. Increasing solvent vapour concentrations shift the absorbance maximum to smaller wavelengths, e.g., as observed for THF. Additionally, CLCs have been coated on acoustic devices such as the quartz crystal microbalance (QCM) to measure the frequency shift of analyte samples at similar concentration levels. The mass effect for tetrachloroethylene was about six times higher than chloroform. Thus, optical response can be correlated with intercalation in accordance to mass detection. The mechanical stability was gained by combining CLCs with imprinted polymers. Therefore, pre-concentration of solvent vapours was performed leading to an additional selectivity. Molecular Diversity Preservation International (MDPI) 2010-05-12 /pmc/articles/PMC3292152/ /pubmed/22399912 http://dx.doi.org/10.3390/s100504887 Text en © 2010 by the authors; licensee MDPI, Basel, Switzerland. This article is an Open Access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/). |
spellingShingle | Article Mujahid, Adnan Stathopulos, Helen Lieberzeit, Peter A. Dickert, Franz L. Solvent Vapour Detection with Cholesteric Liquid Crystals—Optical and Mass-Sensitive Evaluation of the Sensor Mechanism(†) |
title | Solvent Vapour Detection with Cholesteric Liquid Crystals—Optical and Mass-Sensitive Evaluation of the Sensor Mechanism(†) |
title_full | Solvent Vapour Detection with Cholesteric Liquid Crystals—Optical and Mass-Sensitive Evaluation of the Sensor Mechanism(†) |
title_fullStr | Solvent Vapour Detection with Cholesteric Liquid Crystals—Optical and Mass-Sensitive Evaluation of the Sensor Mechanism(†) |
title_full_unstemmed | Solvent Vapour Detection with Cholesteric Liquid Crystals—Optical and Mass-Sensitive Evaluation of the Sensor Mechanism(†) |
title_short | Solvent Vapour Detection with Cholesteric Liquid Crystals—Optical and Mass-Sensitive Evaluation of the Sensor Mechanism(†) |
title_sort | solvent vapour detection with cholesteric liquid crystals—optical and mass-sensitive evaluation of the sensor mechanism(†) |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3292152/ https://www.ncbi.nlm.nih.gov/pubmed/22399912 http://dx.doi.org/10.3390/s100504887 |
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