Patent ID: 7754493

Claim:
A method for measuring a change in surface plasmon resonance, which comprises: (i) introducing a reference liquid containing no test substance to be measured to a surface plasmon resonance measurement device comprising a flow channel system having a cell formed on a metal film and a light-detecting means for detecting the surface plasmon resonance by measuring the intensity of a light beam totally reflected on the metal film; (ii) applying the light beam, and detecting the surface plasmon resonance by measuring the intensity of the light beam totally reflected on the metal film when the reference liquid is contained in the flow channel system; (iii) removing the reference liquid and introducing a sample liquid containing a test substance to be measured into the surface plasmon resonance measurement device; (iv) applying the light beam, and detecting the surface plasmon resonance by measuring the intensity of the light beam totally reflected on the metal film when the sample liquid is contained in the flow channel system; and (v) measuring a change in surface plasmon resonance between the surface plasmon resonance in step (ii) and the surface plasmon resonance in step (iv); wherein a major axis of one or more exposed surfaces of the metal film is between 0.1 μm and 100 μm; wherein a molecule interacting with the test substance is immobilized on the one or more exposed surfaces; wherein the distance between the one or more exposed surfaces is between 200 μm and 10 mm; and wherein the molecule interacting with the test substance is not immobilized on any parts other than the one or more exposed surfaces.