Laser-based isomer identification in the vapor phase

Infrared spectroscopy and mass spectrometry have long been reported as the most selective analytical techniques. Sensitive laser-based detection schemes for infrared spectroscopy such as photoacoustic, cavity ring-down or multipass transmission can be found in a countless number of gas sensing devices. These methods are however not suitable for recording vapors, particularly when high temperatures are involved. This issue has brought us to design and implement a high-temperature multipass cell (HTMC). This novel type of long path absorption cell is heatable up to 723 K and has a variable optical pathlength of up to 35 m. In addition to gases, a condensed sample can be introduced into the cell and analyzed in the vapor phase. The mirrors are separately heated in order to avoid condensation on their optical surface. Furthermore, a compensation mechanism for thermal expansion has been developed to prevent fatal optical misalignments.