Spectroscopic systems for the analysis of small and very small quantities of substances

Spectroscopic system for conducting micro-analytical procedures, wherein at least one sample is directionally illuminated by light emitted from a light source, and the light coming from the sample is concentrated on the entrance slit of at least one spectrometer, wherein for achromatic optical energy transfer aperture changers, an inlet aperture changer provided in an object space between the sample and light source or its image, an outlet aperture changer provided in the object space between the sample and the entrance slit, each of said aperture changers comprising a coaxial, cone-shaped member having a light entry port and a light exit port, the larger one of the ports facing the sample, the light source being a point source of light which is imaged, by means of an aspherical mirror and is transmitted to the entry port of the inlet aperture changer, the spectrometer comprising a simultaneous spectrometer whose diffraction grating is a holographic concave grating and whose receiving unit is a line of photodiodes, the sample being contained in a capillary cell arranged between the aperture changers along the optical axis such that it is irradiated in the longitudinal direction with little inclination of rays with respect to the optical axis.