Surface plasmon resonance

Surface plasmon resonance ( surface plasmon resonance spectroscopy English SPR ) spectroscopy is a spectroscopic analysis method which is used for rapid and easy quantitative measurement of layer thicknesses in the nanometer range. Surface plasmon resonance spectroscopy finds application especially in materials science in the measurement of the adsorption of substances, and in biochemistry in the context of chip laboratory techniques.

Operation

TM polarized light with the analyte to be excited surface plasmons on a thin metal layer on the metal /. This is done by radiation by a prism in total reflection on the side facing away from the analyte. Without analyte, the intensity of the total angular range of the reflected light at a certain angle to a minimum. The refractive index of the analyte will affect this sensitive the excitation conditions and thus the angle of the minimum.

Experimental setup

There are two different possibilities for the arrangement: first, the Otto method, in which an air gap between the prism and the metal to be examined is left. On the other hand the Kretschmann method in which a thin metal film is applied to the prism.

Application

The technology is currently being used extensively in drug research, as used to investigate their binding characteristics of potential new drugs and have it checked. Use of the method is therefore typically an independent ( orthogonal ) Secondary experiment on the high- throughput screening.

The Kretschmann method finds its application in biology. Here is prepared in a prism with a gold film, a membrane, the biological molecules can absorb. The coverage of the membrane with molecules alters the refractive index of the layer, which can be measured very sensitively with this method.