Active Concentration-Independent Chemical Identification With a Tunable Infrared Sensor

Abstract

This paper presents an active-sensing framework for concentration-independent identification of volatile chemicals using a tunable infrared interferometer. The framework operates in real time to generate a sequence of absorption lines that can best discriminate among a given set of chemicals. The active-sensing algorithm was previously developed to optimize temperature programs for metal-oxide chemosensors. Here, we adapt it to tune a nondispersive infrared spectroscope on the basis of a Fabry-Pérot interferometer (FPI). We also extend this framework to allow the identification of chemical samples irrespective of their concentrations. Therefore, we use nonnegative matrix factorization to create concentration-independent absorption profiles of different chemicals, and then employ linear least squares to fit sensor observations to the response profiles. We tested the framework on a simulated classification problem with 27 chemicals and compared against a passive sensing approach; the active-sensing consistently outperformed the passive sensing in terms of classification performance for various sensing budgets and at various levels of sensor noise. We also validated the approach experimentally using a commercial FPI sensor and a database of eight household chemicals. Our results show that the method can predict the sample identity irrespective of concentration.

A fast MEMS infrared microspectrometer for the measurement of hydrocarbon gases

“…The set-up and operation principle of µFPF-based gas sensor remains basically the same compared to conventional NDIR instruments (Fig 1). Many papers report on the application of this type of sensor to a variety of measurement problems and in particular to hydrocarbon gas sensing [4,5]. The absorption bands of hydrocarbon species are spread throughout the near and mid infrared range.…”

Identification of natural rubber samples for high-voltage insulation applications

“…The non-destructive nature of ATR-FTIR, makes it suitable to be applied in process control for industrial applications. FTIR is among the most applied infrared techniques, because it offers high resolution spectra [30]. FTIR has been applied in the rubber industry for determining the content of vulcanizing accelerators and antioxidants [31] or to identify structural changes when applying a mechanicochemical devulcanization process [32].…”