초록 ▼

An infrared spectrometer for the determination of isotopic ratios of gaseous compounds includes a broad-band infrared light source, a spectral selector, a sample compartment, an infrared detector, and a processor. The spectral selector selectively transmits a wavelength window of infrared light cove

An infrared spectrometer for the determination of isotopic ratios of gaseous compounds includes a broad-band infrared light source, a spectral selector, a sample compartment, an infrared detector, and a processor. The spectral selector selectively transmits a wavelength window of infrared light covering a range of wavelengths in which the wavelength window can be selected alternatively to overlap with a wavelength range primarily absorbed by a compound with a first isotope or by the compound with a second isotope. The sample compartment holds a gas sample and includes a gas inlet and a gas outlet. The infrared spectrometer 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 a particular multipass optical cell that includes a field mirror and a multi-segment objective mirror.

대표청구항 ▼

1. A multipass optical cell comprising:a field mirror having a focal length and a center axis; a two segment objective mirror generally facing the field mirror wherein the two segments are displaced from each other to move their respective focal points away from each other; and a prismatic mirror di

1. A multipass optical cell comprising:a field mirror having a focal length and a center axis; a two segment objective mirror generally facing the field mirror wherein the two segments are displaced from each other to move their respective focal points away from each other; and a prismatic mirror displaced from the field mirror by less than about 20 percent of the focal length of the field mirror, wherein the edge of intersecting faces of the prismatic mirror is generally oriented toward the objective mirror and wherein the plane bisecting the two faces of the prismatic mirror pass through the two segments of the objective mirror.