Effect of humidity on the simultaneous detection of carbon dioxide and ethylene in CO2 laser-based photoacoustic spectroscopy

Abstract

We determine the effect of humidity on the multicomponent gas analysis using carbon dioxide (CO₂) laser-based photoacoustic spectroscopy. The PA gas detection system is mainly composed of a modulated CO₂ laser and a resonant PA cell containing the gas mixture (sample) to be analyzed. The PA setup was calibrated for the simultaneous detection of CO₂ and  ethylene (C₂H₄) with varying humidity conditions. The calibration graphs obtained were used  in mapping the concentrations of CO₂ and C₂H₄ emitted by a group of mangoes. The effect of humidity manifested in the phase difference of the modulating signal and the detected acoustic signal.