Simultaneous detection of trace gases using multiplexed tunable diode lasers and a photoacoustic cell containing a cantilever microphone
Simultaneous detection of trace gases using multiplexed tunable diode lasers and a photoacoustic cell containing a cantilever microphone
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DOI：
10.1007/s00340-012-4980-2
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发表时间：
2012-06-01
影响因子：
2.1
通讯作者：
Martin, P. A.
中科院分区：
文献类型：
--
作者：
McNaghten, E. D.;Grant, K. A.;Martin, P. A.
我们报告了我们认为是使用含有悬臂麦克风的细胞通过近红外可调谐二极管激光光声光谱同时检测多种微量气体的新演示。通过调制频分复用四路近红外可调谐二极管激光器的输出，实现了氮基混合气体中一氧化碳（CO）、乙炔（C2H2）、甲烷（CH4）和一氧化碳/二氧化碳（CO+CO2）的同时检测。在常压下同时检测CO、C2H2和CH4，得到了3.4 × 10（-9）、3.6 × 10（-9）和1.4 × 10(-9) cm(-1) W Hz（-1/2）的归一化噪声等效吸收系数。在相应的激光功率下，在2.6 s的测量周期内，噪声当量检测限分别为249.6 ppmv （CO）、1.5 ppmv （C2H2）和293.7 ppmv （CH4）。系统的性能不受部署的激光数量的影响，而激光是由环境声效应引起的主要噪声源。结果表明，小体积光声电池可以与低光功率可调谐二极管激光器配合使用，以高灵敏度和特异性快速同时检测痕量气体。
We report what we believe to be a novel demonstration of simultaneous detection of multiple trace gases by near-IR tunable diode laser photoacoustic spectroscopy using a cell containing a cantilever microphone. Simultaneous detection of carbon monoxide (CO), ethyne (C2H2), methane (CH4) and combined carbon monoxide/carbon dioxide (CO+CO2) in nitrogen-based gas mixtures was achieved by modulation frequency division multiplexing the outputs of four near-IR tunable diode lasers. Normalized noise-equivalent absorption coefficients of 3.4x10(-9), 3.6x10(-9) and 1.4x10(-9) cm(-1) W Hz(-1/2) were obtained for the simultaneous detection of CO, C2H2 and CH4 at atmospheric pressure. These corresponded to noise-equivalent detection limits of 249.6 ppmv (CO), 1.5 ppmv (C2H2) and 293.7 ppmv (CH4) respectively over a measurement period of 2.6 s at the relevant laser power. The performance of the system was not influenced by the number of lasers deployed, the main source of noise arising from ambient acoustic effects. The results confirm that small-volume photoacoustic cells can be used with low optical power tunable diode lasers for rapid simultaneous detection of trace gases with high sensitivity and specificity.