M.A.T.H: Methanol vapor analytics through handheld sensing platform
By Banga, Ivneet; Paul, Anirban; Sardesai, Abha Umesh; Muthukumar, Sriram; Prasad, Shalini
Published in Electrochimica Acta
2021
Abstract
Volatile organic compounds are depicted as biomarkers in numerous respiratory diseases as well as in environment pollution. Methanol is a VOC that is a well-established biomarker and produced exogenously as well as endogenously in both these cases, hence there is a critical need for a versatile sensor system that can measure methanol from the lower parts-per-million to 1000 parts-per million. This paper presents the development of a new miniaturized electrochemical gas sensing platform for the rapid measurement and detection of methanol vapors in the environment. The sensor uses a nafion-Room Temperature Ionic Liquid (RTIL) modified planar interdigitated electrode platform that helps in fast gas diffusion and is incorporated onto an IoT-based platform for on-site monitoring. The designed miniaturized VOC sensor can measure methanol concentrations as low as 1 PPM and provides enhanced sensitivity, specificity, linearity, and repeatability as validated for methanol vapor monitoring. This sensor can detect a wide dynamic range of 1–1000 PPM of methanol vapor using 1-butyl-3-methyl-imidazolium chloride ([BMIM]Cl) as RTIL and has a response time of 5 s, which allows for faster detection. We have achieved a LOD of 1 PPM for methanol detection by quantifying the diffusion current and charge modulations arising within the electrical double layer from the RTIL-methanol interactions through DC-based chronoamperometry. The electrochemical aspect of the RTIL-methanol interaction has been further characterized by chronocoulometry and electrochemical impedance spectroscopy. We have leveraged the electrochemical properties of nafion-[BMIM]Cl crosslinked polymeric network for detecting methanol vapor and developed an electrochemical sensor that can serve as a robust and sensitive platform for on-site detection. In this work, we have demonstrated the development and proof-of-feasibility of an electrochemical RTIL-based sensor prototype for methanol detection in ambient environment. The portability, small form factor, embedded RTIL sensing element, integrability with low-power microelectronic, and an IoT interface makes this methanol sensor prototype a potential application for human health and work safety monitoring. The developed sensor platform is a promising step toward building a next generation rapid, IoT-based microelectronic device for monitoring and detection of methanol vapors even in very low concentration.