Fraunhofer Institute for Physical Measurement Techniques IPM, 79110 Freiburg im Breisgau, Germany.
Department of Microsystems Engineering-Institut für Mikrosystemtechnik (IMTEK), University of Freiburg, 79110 Freiburg im Breisgau, Germany.
Sensors (Basel). 2024 Jan 11;24(2):457. doi: 10.3390/s24020457.
A photoacoustic sensor system (PAS) intended for carbon dioxide (CO) blood gas detection is presented. The development focuses on a photoacoustic (PA) sensor based on the so-called two-chamber principle, i.e., comprising a measuring cell and a detection chamber. The aim is the reliable continuous monitoring of transcutaneous CO values, which is very important, for example, in intensive care unit patient monitoring. An infrared light-emitting diode (LED) with an emission peak wavelength at 4.3 µm was used as a light source. A micro-electro-mechanical system (MEMS) microphone and the target gas CO are inside a hermetically sealed detection chamber for selective target gas detection. Based on conducted simulations and measurement results in a laboratory setup, a miniaturized PA CO sensor with an absorption path length of 2.0 mm and a diameter of 3.0 mm was developed for the investigation of cross-sensitivities, detection limit, and signal stability and was compared to a commercial infrared CO sensor with a similar measurement range. The achieved detection limit of the presented PA CO sensor during laboratory tests is 1 vol. % CO. Compared to the commercial sensor, our PA sensor showed less influences of humidity and oxygen on the detected signal and a faster response and recovery time. Finally, the developed sensor system was fixed to the skin of a test person, and an arterialization time of 181 min could be determined.
本文介绍了一种用于检测二氧化碳（CO）血液气体的光声传感器系统（PAS）。该系统的开发重点是基于所谓的双腔原理的光声（PA）传感器，即包括测量池和检测室。其目的是可靠地连续监测经皮 CO 值，这在重症监护病房患者监测等方面非常重要。使用峰值波长为 4.3 µm 的红外发光二极管（LED）作为光源。一个微机电系统（MEMS）麦克风和目标气体 CO 位于密封的检测室内，用于选择性地检测目标气体。基于在实验室设置中进行的模拟和测量结果，开发了一种小型化的 PA CO 传感器，其吸收路径长度为 2.0 mm，直径为 3.0 mm，用于研究交叉灵敏度、检测限以及信号稳定性，并与具有类似测量范围的商业红外 CO 传感器进行了比较。在实验室测试中，所提出的 PA CO 传感器的检测限为 1 体积% CO。与商业传感器相比，我们的 PA 传感器对检测信号的湿度和氧气影响较小，响应和恢复时间更快。最后，将开发的传感器系统固定在测试人员的皮肤上，并确定了 181 分钟的动脉化时间。
