Electrochemical Cell and Optics

Typical electrochemical cells used for ATR-SEIRAS are shown in Fig. 8.4 [28, 29). The cell can be made of either glass or plastics such as Kel-F. The prism works as the cell window as well as the substrate on which a thin-film electrode is deposited. Infrared-transparent materials with high reflective indices such as 

The sharp peak around 20° corresponds to the surface plasmon excitation, but this arises from the modeling and does not actually occur. The intensity for s-polarization is neghgibly small and thus omitted in the figure. The polarization dependence arises from the constructive and destructive interactions of multiple reflected p- and s-polarized radiations, respectively, within the metal layer [23]. 

This plot shows that the maximum sensitivity is obtained by using p-polarized radiation at a high incident angle around 80°. The use of the high incident angle is also favorable for reducing the absorption by the solution due to the decrease in the penetration depth of the evanescent wave. Nevertheless, two issues should be noted about the optical conditions in the practical measurements. 

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Most commercial flue gas analyzers use electrochemical cells and optical spectrometry. Because of the high temperature and dusty and harsh environment these... 

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