JPS6488339A - Base sequence determination device - Google Patents

Abstract

PURPOSE:To enable the photodetection of the fluorescence in a 90 deg. direction where the Rayleigh scattering of excitation light is smallest by providing a migration gel and excitation light beam as well as a detector part, etc. CONSTITUTION:The excitation light beam 32 scanned in the direction orthogonal with the migration direction by a galvanomirror 34 escapes in the normal direction of the migration gel 2 at all the boundary faces with the gel 2 and, therefore, multireflections do not take place. Fluorescence is emitted from the nucleic acid fragments migrating in the gel 2 and propagates in the gel 2. The fluorescent light appearing at the end face of the gel 2 is detected 56 through light guides 50, 52 and an optical fiber bundle 54 and is converted to an electric signal. The signal indicating the projection position of the beam 32 onto the gel 2 from the rotating angle of the mirror 34 is taken into a signal processing part 58 which takes the fluorescent light in said position therein as the detection signal of a detector part 56. The development pattern of the DNA fragment specimen developed by electrophoresis in the gel 2 is obtd. as the fluorescent detection signal of the detector part 56 by scanning the entire surface of the gel 2 by the mirror 34 in such a manner. The direction where the fluorescent light is photodetected is 90 deg. with the beam 32 and the propagation of the Rayleigh scattering light is minimized.