Quartz‐Enhanced Photoacoustic Sensors for Detection of Eight Air Pollutants
Raffaele De Palo, Arianna Elefante, Gabriele Biagi, Francesco Paciolla, Robert Weih, Valeria Villada, Andrea Zifarelli, Marilena Giglio, Angelo Sampaolo, Vincenzo Spagnolo, Pietro Patimisco
Abstract
A quartz‐enhanced photoacoustic spectroscopy sensor architecture capable of detecting eight different air pollutants (CH 4 , NO 2 , CO 2 , N 2 O, CO, NO, SO 2 , and NH 3 ) is reported. Each analyte is targeted using the same sensor components (acoustic detection module, quartz‐tuning fork, etc.) and a dedicated laser source. Both interband cascade lasers and quantum cascade lasers are employed to target a well‐resolved and isolated absorption feature from each investigated gas, in a wavelength ranging from 3.35 to 9.06 μm. The sensor is calibrated with certified concentrations of each gas species, in a wet nitrogen matrix. For each analyte, the optimal pressure is determined. Minimum detection limits of 40, 13, 800, 230, 450, 78, 18, and 5.8 ppb are obtained for CH 4 , NO 2 , CO 2 , N 2 O, CO, NO, SO 2 , and NH 3 , respectively, at 100 ms of integration time.