Patent ID: 7884934

Claim:
A method for measuring respective concentrations of a first antigen and a second antigen contained in a test solution by using an apparatus for biogenic substance concentration measurement, having the steps of: preparing said apparatus for biogenic substance concentration measurement, said apparatus comprising: a cell comprising therein a first region, a second region, and a test solution retention space; a light source; a polarizing plate for polarizing light radiated from said light source; and a photoreceiver for receiving light transmitted through said cell along an optical axis intersecting with said first region, said second region, and said test solution retention space, wherein a plurality of first metallic nanorods each having a first antibody on a surface thereof are immobilized on said first region, a plurality of second metallic nanorods each having a second antibody on a surface thereof are immobilized on said second region, the respective long axes of said plurality of first metallic nanorods are aligned in the same direction, the respective long axes of said plurality of second metallic nanorods are aligned in the same direction, the long-axis direction of said first metallic nanorod is orthogonal to the long-axis direction of said second metallic nanorod, and at least one of said polarizing plate and said cell is capable of rotation with said optical axis as the rotation axis, supplying said test solution to said test solution retention space to allow said first antigen and said second antigen to react with said first antibody and said second antibody, respectively, transmitting along said optical axis a polarized light parallel to the long-axis direction of said plurality of first metallic nanorods to receive with said photoreceiver a first light thus obtained, rotating at least one of said polarizing plate and said cell to set a polarized light transmitted through said polarizing plate to be parallel to the long-axis direction of said plurality of second metallic nanorods, transmitting along said optical axis said polarized light parallel to the long-axis direction of said plurality of second metallic nanorods to receive with said photoreceiver a second light thus obtained, and calculating the respective concentrations of said first antigen and said second antigen based respectively on said first light and said second light.