Patent ID: 7330263

Claim:
A measurement method for analyzing an analysis object molecule by using a measurement apparatus utilizing attenuated total reflection, the apparatus including: a light source for generating a light beam; a measurement chip having a dielectric block transparent to the light beam, a thin film layer formed on a face of the dielectric block, and a sample retention mechanism for retaining a sample including the analysis object molecule on the surface of the thin film; an incident light beam optical system for causing the light beam to enter the dielectric block at an incident angle so that total reflection conditions are satisfied at the interface between the dielectric block and the thin film layer; and a measurement means for measuring the position of a dark line in the light beam totally reflected at the interface, the method comprising the steps of: measuring the position of the dark line while causing a reference molecule, of substantially the same size and substantially the same refractive index as the analysis object molecule, to adhere onto the thin film layer of the measurement chip; removing the reference molecule from the thin film layer; measuring the position of the dark line while causing the measurement chip to retain the sample; and calibrating the sensitivity of the measurement means, based on the measurement result of the position of the dark line while the reference molecule is adhered to the thin film, for each measurement chip.