A device adapted for spectral analysis having a transmitting means adapted for electromagnetic radiation, a delimited space,in the form of a cavity, serving as a measuring cell and intended to be capable of defining an optical measuring distance, a sensing means of the electromagnetic radiation passing the optical measuring distance from said transmitting means, and a unit at any rate connected to the sensing means performing the spectral analysis, the sensing means for the electromagnetic radiation is opto-electrically adapted sensitive to the electromagnetic radiation, which is intended to fall within the spectral range whose chosen wavelength components or spectral elements are to become objects of an analysis in the unit performing the spectral analysis for determining in this unit, over calculations, the relative intensity of radiation of the spectral element.