A Selective Benzene, Acetylene, and Carbon Dioxide Sensor in the Fingerprint Region

TL;DR

This paper presents a laser-based sensor using quantum cascade lasers and advanced spectroscopy techniques for selective, interference-free detection of benzene, acetylene, and CO2 at ambient conditions with high sensitivity.

Contribution

It introduces a novel mid-infrared laser sensor employing multidimensional linear regression for interference-free trace gas detection.

Findings

Achieved detection limits of 0.11 ppm for benzene, 4.16 ppm for acetylene, and 2.96 ppm for CO2.

Demonstrated insensitivity to spectral overlaps, ensuring accurate measurements.

Validated sensor performance with laboratory-prepared mixture samples.

Abstract

A mid-infrared laser-based sensor is designed and demonstrated for trace detection of benzene, acetylene, and carbon dioxide at ambient conditions. The sensor is based on a distributed feedback quantum cascade lase and a multidimensional liner (DFB-QCL) emitting near 14.84 um. Tunable diode laser absorption spectroscopy (TDLAS) and a multidimensional linear regression algorithm are employed to enable interference-free measurements of the target species. The laser wavelength was tuned over 673.8-675.1 cm-1 by a sine-wave injection current (1 kHz scan rate). Minimum detection limits of 0.11, 4.16, and 2.96 ppm were achieved for benzene, acetylene, and carbon dioxide, respectively. The developed sensor is insensitive to interference from overlapping absorbance spectra, and its performance was demonstrated by measuring known mixture samples prepared in the lab. The sensor can be used to detect tiny leaks of the target species in petrochemical facilities and to monitor air quality in residential and industrial areas.