光学学报, 2018, 38 (12): 1230001, 网络出版: 2019-05-10
基于2.73 μm分布反馈式激光器同时在线测量呼出气体中的CO2和水汽
Simultaneous On-Line Measurement of Exhaled Carbon Dioxide and Water Vapor Based on 2.73 μm Distributed Feedback Laser
光谱学 呼出气体分析 波长调制光谱技术 激光吸收光谱 CO2 水汽 spectroscopy exhaled gas analysis wavelength modulation spectroscopy laser absorption spectroscopy carbon dioxide water vapor
摘要
人体呼出气体中CO2和水汽的浓度变化与身体状况密切相关,因此对其浓度进行检测具有重要意义。提出一种基于2.73 μm分布反馈式激光器的呼出气体检测装置,选取3659.402 cm
-1和3659.934 cm
-1处的谱线,利用波长调制光谱技术分别对人体呼出气体中的CO2和水汽同时进行测量。结果表明:利用二次谐波信号对气体浓度进行定标,当CO2和水汽的体积分数分别小于35%和2.3%时,线性度分别达到0.99945和0.99679;对呼吸循环过程中CO2和水汽的浓度进行实时测量,积分时间为0.92 s时,探测灵敏度分别为4.33×10
-3和1.37×10
-4;在采集时间为56.8 s时,CO2的探测精度为0.12%,在最佳积分时间为17 min时,CO2的探测极限可达到1.49×10
-4。
Abstract
The concentration changes of exhaled carbon dioxide and water vapor are closely related to the physical condition. Therefore, it is of great significance to detect their concentrations. An exhaled gas detection device based on a 2.73 μm distributed feedback laser is proposed. Spectral lines at 3659.402 cm
-1 and 3659.934 cm
-1 are selected to measure carbon dioxide and water vapor respectively by using the wavelength modulation spectroscopy. The results show that using the second harmonic signal to calibrate the gas concentration, the linearity of 0.99945 and 0.99679 is obtained when the volume fractions of carbon dioxide and water vapor are less than 35% and 2.3%, respectively. The concentrations of carbon dioxide and water vapor during the respiratory cycle are measured in real time. With the measurement time of 0.92 s, the sensor achieves a detection sensitivity of 4.33×10
-3 and 1.37×10
-4 for carbon dioxide and water vapor, respectively. At the acquisition time of 56.8 s, the detection accuracy with 0.12% of carbon dioxide is achieved, and a detection limit of 1.49×10
-4 at the optimal integration time of 17 min is achieved for carbon dioxide measurement.
吴涛, 张怀林, 孔维平, 何兴道, 陈忠平, 陈卫东. 基于2.73 μm分布反馈式激光器同时在线测量呼出气体中的CO2和水汽[J]. 光学学报, 2018, 38(12): 1230001. Tao Wu, Huailin Zhang, Weiping Kong, Xingdao He, Zhongping Chen, Weidong Chen. Simultaneous On-Line Measurement of Exhaled Carbon Dioxide and Water Vapor Based on 2.73 μm Distributed Feedback Laser[J]. Acta Optica Sinica, 2018, 38(12): 1230001.