Abstract
This chapter intends to cover the instrumentation of gas phase Fourier transform infrared spectroscopy (FT-IR), its recent advancement, and applications. The major focus have been given to the principle and data acquisition scheme of the repetitive mode measurement method of FT-IR spectrometer. The application of this spectroscopy in the isomeric identification of the methylated polycyclic aromatic hydrocarbons (MPAHs) and the conformational analysis of diols have been discussed. Furthermore, the application of the repetitive measurement mode of FT-IR combined with the UV laser in monitoring the atmospherically relevant photochemical reactions has been covered. In conclusion, this chapter briefly summarizes the current applications and discusses future applications of this technique in following drug degradation.