An interferometer for Fourier spectroscopy, wherein the interferometer comprises a beamsplitter (14) and two retroreflectors (20, 26), characterized in that the beamsplitter (14) is mounted movable, e.g., mounted pivotally or displacably, while both retroreflectors (20, 26) are arranged as fixed retroreflectors. The proposed structure is simple to produce, can be made substantially insensible to environmental vibrations, and it is well suited for routine measurements for the determination of quantities of predefined components in a medium. The interferometer is particularly intended for measurements in the mid- or near-infrared range for determination of the quantities of specified components in a medium, and more specifically in a food product, e.g., a liquid such as milk.
This application is the national phase under 35 U.S.C. .sctn.371 of prior PCT International Application No. PCT/DK97/00299 which has an International filing date of Jul. 4, 1997 which designated the United States of America.
