Influence of humidity on accuracy of QCM - IR780-based GUMBOS sensor arrays

Caitlan E Ayala; Stephanie R Vaughan; Rocío L Pérez; Breona S Leonard; Baleigh King; Kyle Jorgensen; Isiah M Warner

doi:10.1016/j.aca.2023.341677

Influence of humidity on accuracy of QCM - IR780-based GUMBOS sensor arrays

Anal Chim Acta. 2023 Oct 16:1278:341677. doi: 10.1016/j.aca.2023.341677. Epub 2023 Aug 16.

Authors

Caitlan E Ayala¹, Stephanie R Vaughan¹, Rocío L Pérez², Breona S Leonard¹, Baleigh King³, Kyle Jorgensen³, Isiah M Warner⁴

Affiliations

¹ Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA.
² Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA; Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, GA, 30458, USA. Electronic address: rperez@georgiasouthern.edu.
³ Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, GA, 30458, USA.
⁴ Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA. Electronic address: iwarner@lsu.edu.

PMID: 37709438
DOI: 10.1016/j.aca.2023.341677

Abstract

Herein, hydrophobic coating materials are reported for QCM detection of VOCs under dry and humid conditions. In this study, IR780-based GUMBOS ([IR780][OTf] and [IR780][NTf2]) were synthesized using an ion exchange reaction and the anions trifluoromethanesulfonimide ([OTf]) and bisperfluoromethanesulfonimide ([NTf2]). The parent iodide salts and GUMBOS ([IR780][I]), [IR780][OTf], and [IR780][NTf2]) were characterized using several analytical techniques. These salts were then employed as sensor coatings on quartz crystal resonators using an electrospray coating method. These sensors were exposed to four flow ratios of five common VOCs in the absence and presence of 10 vol% water. Fundamental frequency responses were recorded and further employed as input variables to develop highly accurate multi-sensor arrays (MSAs). Accuracy was better than 78.3% without water, and better than 91.7% in the presence of water. When multi-harmonic responses were evaluated as input variables to assess discrimination ability for each sensor, highly accurate virtual sensor arrays (VSAs) were developed using each GUMBOS coating. In the case of [IR780][NTf2], a slight improvement in discrimination was achieved in the presence of water (95%) versus the absence of water. Moreover, this study highlights development of readily synthesized hydrophobic coatings of IR780-based GUMBOS for potential detection and discrimination of VOCs in aqueous systems.

Keywords: GUMBOS; Multi-sensor arrays (MSAs); Quartz crystal microbalance (QCM); Virtual sensor arrays (VSAs); Volatile organic compounds (VOCs).