We report on applications of the ultraviolet-light-emitting-diode-based incoherent broadband cavity-enhanced absorption spectroscopy (UV-LED-IBBCEAS) technique for optical monitoring of HONO, NO₂ and CH₂O in a simulation chamber. Performance intercomparison of UV-LED-IBBCEAS with a wet chemistry-based NitroMAC sensor and a Fourier transform infrared (FTIR) spectrometer has been carried out on real-time simultaneous measurement of HONO, NO₂ and CH₂O concentrations during the reaction of NO₂ with H₂O vapour in CESAM (French acronym for Experimental Multiphasic Atmospheric Simulation Chamber). The 1σ (signal-to-noise ratio (SNR) = 1) detection limits of 112 pptv for NO₂, 56 pptv for HONO and 41 ppbv for CH₂O over 120 s were found for the UV-LED-IBBCEAS measurement. On the contrary to many set-ups where cavities are installed outside the simulation chamber, we describe here an original in situ permanent installation. The intercomparison results demonstrate that IBBCEAS is a very well suitable technique for in situ simultaneous measurements of multiple chemically reactive species with high sensitivity and high precision even if the absorption bands of these species are overlapped. It offers excellent capacity for non-invasive optical monitoring of chemical reactions without any perturbation. For the application to simulation chambers, it has the advantage to provide a spatially integrated measurement across the reactor and hence to avoid point-sampling-related artefacts.

中文翻译：

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在模拟室 CESAM 中 NO2 与 H2O 蒸汽反应期间，IBBCEAS、NitroMAC 和 FTIR 分析对 HONO、NO2 和 CH2O 测量的比对

我们报告了基于紫外发光二极管的非相干宽带腔增强吸收光谱 (UV-LED-IBBCEAS) 技术在模拟室中对 HONO、NO ₂和 CH ₂ O进行光学监测的应用。UV-LED-IBBCEAS 与基于湿化学的 NitroMAC 传感器和傅里叶变换红外 (FTIR) 光谱仪的性能比对已在 NO反应过程中实时同时测量 HONO、NO ₂和 CH ₂ O 浓度₂在 CESAM（实验多相大气模拟室的法语首字母缩写词）中 使用 H ₂ O 蒸汽。1 σ （信噪比 (SNR)  = 1) NO _{2 的}检测限为 112 pptv ，HONO 为 56 pptv，CH ₂为 41 ppbv在 UV-LED-IBBCEAS 测量中发现 O 超过 120 秒。与许多在模拟室外部安装腔体的设置相反，我们在此描述了原始的原位永久安装。比对结果表明，IBBCEAS 是一种非常适用于原位同时测量多种化学活性物质的技术，即使这些物质的吸收带重叠，也具有高灵敏度和高精度。它为化学反应的无创光学监测提供了出色的能力，没有任何扰动。对于模拟室的应用，它具有提供跨反应器空间集成测量的优势，从而避免与点采样相关的伪影。