Sensors | |
Improving the Detection Limit in a Capillary Raman System for In Situ Gas Analysis by Means of Fluorescence Reduction | |
Simone Rupp1  Hendrik Seitz-Moskaliuk1  Andreas Off1  Timothy M. James1  Helmut H. Telle2  | |
[1] Institute for Technical Physics, Tritium Laboratory Karlsruhe, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany;Instituto Pluridisciplinar, Paseo Juan XXIII-1, Universidad Complutense, 28040 Madrid, Spain; | |
关键词: Raman spectroscopy; capillary; gas analysis; process control; real-time monitoring; instrument development; fluorescence reduction; | |
DOI : 10.3390/s150923110 | |
来源: DOAJ |
【 摘 要 】
Raman spectroscopy for low-pressure or trace gas analysis is rather challenging, in particular in process control applications requiring trace detection and real-time response; in general, enhancement techniques are required. One possible enhancement approach which enjoys increasing popularity makes use of an internally-reflective capillary as the gas cell. However, in the majority of cases, such capillary systems were often limited in their achievable sensitivity by a significant fluorescence background, which is generated as a consequence of interactions between the laser light and optical glass components in the setup. In order to understand and counteract these problems we have investigated a range of fluorescence-reducing measures, including the rearrangement of optical elements, and the replacement of glass components—including the capillary itself—by metal alternatives. These studies now have led to a capillary setup in which fluorescence is practically eliminated and substantial signal enhancement over standard Raman setups is achieved. With this improved (prototype) setup, detection limits of well below 1 mbar could be obtained in sub-second acquisition times, demonstrating the potential of capillary Raman spectroscopy for real-time, in situ gas sensing and process control applications, down to trace level concentrations.
【 授权许可】
Unknown