muciPRECON: multichannel preconcentrators for portable mid-infrared hydrocarbon gas sensors

Abstract

Enrichment of vapor phase molecules is a crucial step during the detection of environmentally relevant trace gases suitable for detection via compact mid-infrared sensing devices. Methane is among the most abundant greenhouse gases in the troposphere, yet difficult to monitor given its rather low concentration levels. Consequently, for utilizing mobile and compact infrared sensors with limited absorption path lengths for detecting methane, appropriate preconcentration is a prerequisite. The present study introduces a multichannel substrate-integrated preconcentrator (muciPRECON) utilizing Carbosieve S-II/S-III adsorbent materials facilitating thermal desorption of enriched methane directly into a mid-infrared gas sensor based on substrate-integrated hollow waveguides (iHWGs) combined with a portable Fourier transform infrared (FT-IR) spectrometer suitable for in-field operation. With this novel approach, preconcentration factors (PCFs) up to 6.7 and a limit of detection (LOD) of 12 ppm_v using Carbosieve S-II as the sorbent material were achieved.