Two methods have been used to record infrared spectra from separated zones on a thin-layer plate based on either in situ measurement by diffuse reflectance or attenuated total reflectance,or by transmission measurements after extraction and transfer to an infrared transparent substrate [59,96,97]. Thin-layer stationary phases exhibit strong absorption in the mid-infrared rangelimiting the ability to record full spectra using in situ methods. Non-traditional and non-absorbing stationary phases such as lanthanum fluoride and zirconium oxide have been suggested as alternatives to the inorganic oxide materials (e.g., silica gel and alumina) commonly used for separations but are less efficient as a separation medium [59,98].