Abstract: In a method for carrying out a surface plasmon resonance (SPR) measurement a beam of electromagnetic radiation is directed through a part transparent to it onto a surface of a material layer having been brought on its opposite side in contact with a test material. A change in the intensity of the reflected radiation, caused by the resonance phenomenon, is utilized for analyzing the test material. The material layer is of catalytic material, for example palladium, having a negative real part of the dielectric constant at the used wavelength of the electromagnetic radiation and being capable of catalyzing chemical reactions in which the test material takes part. The measurement is carried out at such a wavelength and angle of incidence of the radiation onto the surface that a change resulting from the material concentration accumulated on the opposite side of the material owing to the catalytic properties is detectable in the intensity of the reflected radiation.