Ammonia (NH₃) toxicity, stemming from nitrification, can adversely affect aquatic life and influence the taste and odor of drinking water. This underscores the necessity for highly responsive and accurate sensors to continuously monitor NH₃ levels in water, especially in complex environments, where reliable sensors have been lacking until this point. Herein, we detail the development of a sensor comprising a compact and selective analyzer with low gas consumption and a timely response based on photoacoustic spectroscopy. This, combined with an automated liquid sampling system, enables the precise detection of ammonia traces in water. The sensor system incorporates a state-of-the art quantum cascade laser as the excitation source emitting at 9 μm in resonance with the absorption line of NH₃ located at 1103.46 cm^–1. Our instrument demonstrated detection sensitivity at a low ppm level for the ammonia molecule with response times of less than 60 s. For the sampling system, an ammonia stripping solution was designed, resulting in a prompt full measurement cycle (6.35 min). A further evaluation of the sensor within a pilot study showed good reliability and agreement with the reference method for real water samples, confirming the potential of our NH₃ analyzer for water quality monitoring applications.

中文翻译：

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使用量子级联激光器进行光声光谱分析水溶液中的氨

硝化作用产生的氨 (NH ₃ ) 毒性会对水生生物产生不利影响，并影响饮用水的味道和气味。这强调了需要高度响应和精确的传感器来连续监测水中的 NH ₃水平，特别是在复杂的环境中，迄今为止，这些环境中一直缺乏可靠的传感器。在此，我们详细介绍了一种传感器的开发，该传感器包括紧凑型选择性分析仪，具有低气体消耗和基于光声光谱的及时响应。与自动液体采样系统相结合，可以精确检测水中的氨痕量。该传感器系统采用最先进的量子级联激光器作为激发源，发射波长为 9 μm 的光，与1103.46 cm ^–1处的NH ₃吸收线共振。我们的仪器对氨分子具有低 ppm 水平的检测灵敏度，响应时间小于 60 秒。对于采样系统，设计了氨汽提解决方案，从而实现快速完整的测量周期（6.35 分钟）。在试点研究中对传感器的进一步评估显示出良好的可靠性，并且与实际水样的参考方法一致，证实了我们的 NH ₃分析仪在水质监测应用中的潜力。