The impact of water and hydrocarbon concentration on the sensitivity of a polymer-based quartz crystal microbalance sensor for organic compounds

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Pejcic, Bobby ORCID ID icon; Crooke, Emma; Doherty, Cara; Hill, Anita ORCID ID icon; Myers, Matt; Qi, Xiubin; Ross, Andrew


2011-10-03


Journal Article


Analytica Chimica Acta


703


1


70-79


Long-term environmental monitoring of organic compounds in natural waters requires sensors that respond reproducibly and linearly over a wide concentration range, and do not degrade with time. Although polymer coated piezoelectric based sensors have been widely used to detect hydrocarbons in aqueous solution, very little information exists regarding their stability and suitability over extended periods in water. In this investigation, the influence of water aging on the response of various polymer membranes [polybutadiene (PB), polyisobutylene (PIB), polystyrene (PS), polystyrene-co-butadiene (PSB)] was studied using the quartz crystal microbalance (QCM). QCM measurements revealed a modest increase in sensitivity towards toluene for PB and PIB membranes at concentrations above 90 ppm after aging in water for 4 days. In contrast, the sensitivity of PS and PSB coated QCM sensors depended significantly on the toluene concentration and increased considerably at concentrations above 90 ppm after aging in water for 4 days. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) showed that there is a change in the sorption mechanism at higher toluene levels for PS and PSB. Positron annihilation lifetime spectroscopy (PALS) studies were performed to investigate the free volume properties of all polymers and to monitor any changes in the free volume size and distribution due to water and toluene exposure. The results show that the free volume element size, water permeability, and QCM sensitivity are correlated in these polymer membranes. This study shows that examination of the polymer free volume in membranes can be used to understand and predict sensor properties. The results suggest that polymer membrane conditioning in water is an issue that needs to be considered during QCM measurements. In addition, the study shows that the hydrocarbon response is concentration dependant for polymers with a high glass transition temperature, and this feature is often neglected when comparing sensor sensitivity in the literature.


Elsevier


Quartz crystal microbalance; Attenuated total reflectance; Infrared spectroscopy; Positron annihilation lifetime spectroscopy; Polymer; Hydrocarbon sensor


Sensor Technology (Chemical aspects); Chemical Characterisation of Materials; Analytical Chemistry not elsewhere classified


Submitted to Publisher (pdf) (418KB)


https://doi.org/10.1016/j.aca.2011.07.015


Link to Publisher's Version


Crown copyright © 2011 Published by Elsevier B.V. All rights reserved. NOTICE: this is the author’s version of a work that was accepted for publication in Analytica Chimica Acta. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Analytica Chimica Acta, Volume 703, Issue 1, 3 October 2011, Pages 70–79; DOI: 10.1016/j.aca.2011.07.015


EP111405


Journal article - Refereed


English


Pejcic, Bobby; Crooke, Emma; Doherty, Cara; Hill, Anita; Myers, Matt; Qi, Xiubin; Ross, Andrew. The impact of water and hydrocarbon concentration on the sensitivity of a polymer-based quartz crystal microbalance sensor for organic compounds. Analytica Chimica Acta. 2011; 703(1):70-79. https://doi.org/10.1016/j.aca.2011.07.015



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