INFRARED SPECTROMETER FOR THE MEASUREMENT OF ISOTOPIC RATIOS

摘要

An infrared spectrometer (100) for the determination of isotopic ratios ofgaseous compounds includes a broad-band infrared light source (102), aspectral selector (138), a sample compartment (106), an infrared detector(112), and a processor (114). The spectral selector (138) selectivelytransmits a wavelength window of infrared light covering a range ofwavelengths in which the wavelength window can be selected alternatively tooverlap with a wavelength range primarily absorbed by a compound with a firstisotope or by the compound with a second isotope. The sample compartment (108)helds a gas sample and includes a gas inlet and a gas outlet. The infraredspectrometer (100) can be used to detect isotopic ratios of carbon dioxide,where enhancement of 13CO2 can indicate metabolic activity of an infection,for example by H. pylori, or of specific enzymes. Preferred embodiments use aparticular multipass optical cell (400) that includes a field mirror (404) anda multi-segment objective mirror (406).