实验技术与管理2025，Vol.42Issue(5)：155-160,6.DOI:10.16791/j.cnki.sjg.2025.05.019
基于光声光谱技术的人体呼吸气检测实验装置设计
Design of a body breath gas detection device based on photoacoustic spectroscopic technology
摘要
Abstract
[Objective]Photoacoustic spectroscopy-based trace gas detection technology is known for its high sensitivity and rapid response times.The all-optical photoacoustic spectroscopy technique,which replaces traditional capacitive acoustic sensors with fiber-optic microphones,offers a compact design,enhanced sensitivity,an improved signal-to-noise ratio,and broader application possibilities.Given that exhaled breath contains trace gases associated with various diseases,researchers are actively working to accelerate detection times and enhance efficiency,thereby advancing multigas real-time monitoring techniques.[Methods]This study presents the design of a compact teaching experimental apparatus for medical exhaled gas detection using all-optical photoacoustic spectroscopy.The apparatus is designed to measure the methane and ammonia concentrations in human exhalation;it comprises distributed feedback semiconductor lasers,a fiber-optic acoustic sensor,and a T-type resonant photoacoustic cell.The cantilever beam in the fiber-optic sensor plays a critical role in device performance.Computational simulations were used to determine the cantilever beam's optimal dimensions as 1.3 mm in length,0.8 mm in width,and 3.9 μm in thickness,with a 5 μm gap and a resonance frequency of 3,200 Hz.The central wavelengths of the two distributed feedback semiconductor lasers were set at 1,653.7 nm and 1,531.5 nm,corresponding to the absorption peaks of methane and ammonia,respectively.The laser modulation frequencies were tuned to match the resonance frequencies of the fiber-optic acoustic sensor and the T-type resonant photoacoustic cell.Wavelength-division multiplexing was employed to couple the two laser beams into the photoacoustic cell,where the fiber-optic acoustic sensor detected dual-frequency photoacoustic signals generated by the photoacoustic effect.Data processing was handled using LabVIEW to extract concentration information,enabling simultaneous measurement of methane and ammonia.Prior to experimentation,the laser's modulation frequencies were calibrated by measuring the resonance frequencies of the photoacoustic cell and acoustic sensor.Nitrogen was utilized to establish gas concentrations,allowing the relationship between gas concentrations and photoacoustic signals to be determined,which subsequently facilitated sensitivity calculations.When used,students exhaled into the system via a water-resistant device.The system measured methane and ammonia concentrations in real time and yielded experimental results.[Results]The experimental system demonstrated detection limits of 0.31 μL/L for methane and 45 nL/L for ammonia,meeting warning thresholds for a healthy physiological state.If ammonia concentrations fell outside the range of 200～1,750 nL/L,the LabVIEW interface displayed a warning prompt:"Abnormal ammonia concentration."Similarly,methane concentrations exceeding 3 μL/L triggered the prompt"Abnormal methane concentration."When both gases were within normal ranges,the system displayed"Healthy."Experimental validation confirmed that the system accurately displayed these results following exhalation.[Conclusions]The experimental system described herein enables real-time measurement of methane and ammonia in human exhaled breath.With its compact size,minimal gas requirements,and rapid detection capabilities,this system is well-suited for experimental teaching applications,achieving the anticipated design objectives.关键词
全光学光声光谱/呼吸气检测/光纤声波传感器/实验教学Key words
all-optical photoacoustic spectroscopy/breath gas detection/fiber-optic acoustic sensor/experimental teaching分类
信息技术与安全科学引用本文复制引用
宫振峰,张馨予,梅亮..基于光声光谱技术的人体呼吸气检测实验装置设计[J].实验技术与管理,2025,42(5):155-160,6.基金项目
国家自然科学基金项目(62375035) （62375035）
大连理工大学教育教学改革基金项目(YB2024018) （YB2024018）
