Non-injective gas sensor arrays: identifying undetectable composition changes

16 August 2021, Version 2
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

A gravimetric, MOF-based (MOF = metal-organic framework) sensor array functions by measuring the mass of gas adsorbed in an array of MOFs. Changes in the gas composition are expected to produce detectable changes in the mass of gas adsorbed in the MOFs. In practical settings, multiple components of the gas adsorb into the MOFs. As a result, the map from gas compositions to sensor response vectors will be non-injective (many-to-one). Here, we outline a mathematical method to determine undetectable changes in gas composition to which non-injective gas sensor arrays are unresponsive. This is important for understanding their limitations and vulnerabilities. Our method relies on a mixed-gas adsorption model in the MOFs comprising the sensor array. We illustrate the identification of unresponsive subspaces and ranked responsive directions for gas sensor arrays based on Co-MOF-74 and HKUST-1 aimed at quantitative sensing of CH4/N2/CO2/C2H6 mixtures (relevant to the natural gas industry).

Keywords

sensor array
gas sensors
MOFs
QCM-MOF sensors
MOF thin film
electronic nose

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.