Horká V, Civis S, Xu Li-Hong, Lees R M
J. Heyrovský Institute of Physical Chemistry, Academy of Science of the Czech Republic, Dolejskova 3, 18223 Prague 8, Czech Republic.
Analyst. 2005 Aug;130(8):1148-54. doi: 10.1039/b503838c. Epub 2005 Jun 10.
A new technique for high resolution photoacoustic detection based on application of laser diodes has been developed. This method was tested and compared using identical photoacoustic instrumentation (cell and microphone) to study gas absorption in three different spectral regions, namely: the infrared range near 2100 cm(-1), CO and OCS fundamental band absorption; the ranges near 4200 and 4350 cm(-1), CH4, NH3 and N2O overtone and combination band absorption; the near infrared range near 6500 cm(-1), CO, CO2 and NH3 overtone absorption. Several types of diode laser operating at room temperature or at liquid nitrogen temperature were compared. The optimum gas pressures for the maximum sensitivity of the photoacoustic signals were found and the detection limits were estimated for all of the gases studied. The best sensitivity was achieved for NH3 at 100 ppbv. The sensitivity of the developed system was tested on detection of traces of NH3 and CO2 gases from car exhaust.
一种基于激光二极管应用的高分辨率光声检测新技术已被开发出来。使用相同的光声仪器（样品池和麦克风）对该方法进行了测试和比较，以研究三种不同光谱区域的气体吸收，即：2100 cm(-1)附近的红外区域，CO和OCS基频带吸收；4200和4350 cm(-1)附近的区域，CH4、NH3和N2O泛音及组合带吸收；6500 cm(-1)附近的近红外区域，CO、CO2和NH3泛音吸收。比较了几种在室温或液氮温度下工作的二极管激光器。找到了光声信号最大灵敏度的最佳气体压力，并对所有研究气体的检测限进行了估计。对于NH3，在100 ppbv时实现了最佳灵敏度。所开发系统的灵敏度在检测汽车尾气中的痕量NH3和CO2气体方面进行了测试。
