Ppb-level detection of ammonia based on QEPAS using a power amplified laser and a low resonance frequency quartz tuning fork

Abstract

Abstract:In this report, an ultra-high sensitive quartz-enhanced photoacoustic spectroscopy (QEPAS) based ammonia (NH 3 ) sensor using a power amplified diode laser and a low resonance frequency quartz tuning fork (QTF) was demonstrated for the first time. A fibercoupled, continuous wave (CW), distributed feedback (DFB) diode laser with a watt level output power boosted by an erbium-doped fiber amplifier (EDFA) was used as the QEPAS excitation source. A QTF with a resonance frequency of 30.72 kHz was employed as an acoustic wave transducer. The modulation depth in the wavelength modulation spectroscopy (WMS) based QEPAS system was optimized theoretically and validated by experimental measurements. For the reported NH 3 sensor system, a 418.4 ppbv (parts per billion by volume) minimum detection limit at a NH 3 absorption line of 6533.4 cm −1 was achieved when the modulation depth was set to the optimum value of 0.188 cm −1 . The ppb-level detection sensitivity verified the design of the reported QEPAS method and makes it suitable for use in environmental monitoring and other applications. Patni, "Atmospheric nitrogen compound II: emissions, transport, transformation, deposition and assessment," Atmos. Environ. 35, 1903Environ. 35, -1911Environ. 35, (2000. 3. K. W. van der Hoek, "Estimating ammonia emission factors in Europe: summary of the work of the UNECE ammonia expert panel," Atmos. Environ. 32, 315-316 (1998). 4. G. P. Wyers, R. P. Otjes, and J. Slanina, "A continuous-flow denuder for the measurement of ambient concentration and surface-exchange fluxes of ammonia," Atmos. Environ. 27a, 2085-2090 (1993).

Review of Recent Advances in QEPAS-Based Trace Gas Sensing

“…Recently, a QEPAS sensor system based on an EDFA-amplified diode laser was successfully used in acetylene (C 2 H 2 ), hydrogen sulfide (H 2 S), and ammonia (NH 3 ) detection [52][53][54]. In [52], a near-infrared, continuous-wave diode laser with emitting power of 6.7 mW served as the seed laser.…”

“…After being amplified by an EDFA, the laser beam of a diode laser was injected into an acoustic detection module (ADM). For C 2 H 2 , H 2 S, and NH 3 sensing, the detection limits of EDFA-QEPAS sensors were 33.2 ppb (parts per billion by volume) [52], 142 ppb [53], and 418.4 ppb [54], respectively. No signal saturation was observed in these investigations, which means that an EDFA with higher output power can be adopted to further improve the QEPAS sensor performance.…”

Phase Optimized Photoacoustic Sensing of Gas Mixtures

“…Dang et al describe a system optimized for the detection of ammonia with a custom tuning fork and they achieve a sensing limit of 22 ppm [12]. Ma et al reached 418 ppb using a custom tuning fork and an amplified source [13] and Wu et al even reached 17 ppb, also with an amplified excitation source [14].…”

High‐sensitivity detection and quantification of CHCl3 vapors in various gas environments based on the photoacoustic spectroscopy

“…In 1880, Alexander Graham Bell discovered the PA effect. 17 Because of the advantages of this method, after Alexander Graham Bell, this method was developed by various scientists such as Kreuaer 18 ; Viengerov 19 (in order to detect by IR source with high noise); Schafer et al 20 (in order to increase the quality factor of PA cells); Kerr and Atwood 21 (in order to measure the absorption spectrum of water vapor); Bernegger and Sigrist 22 (performed PA spectroscopy of gases and vapors for trace gas analysis); Besson et al 23,24 (provided PA spectroscopy setup by diode laser in order to detect CH 4 and HCl); Gondal and Yamani 25 (for ozone detection); Lima et al 26 (for high-sensitivity detection of 16 ppb ethylene and 42 ppb ammonia); Kumar et al 27,28 (to trace hazardous chemicals by Quantum cascade lasers (QCLs)); Mohebbifar et al 29 and Dibaee et al 30 (in order to obtain high-sensitive spectroscopy of SO 2 , NO 2 , and SF 6 ); Yufei Ma 31 and Yufei Ma et al 32 (for ppb-level detection of ammonia based on QEPAS); and so forth. [33][34][35][36] The PA spectroscopy is based on the absorption of light by the gas.…”