Spectroscopic detector

A spectroscopic detector comprising:

• a light source;
• a flow cell having an internal space through which a sample flows;
• a diffraction grating configured to disperse light from the light source so that intensity of one of plus side diffracted light and minus side diffracted light is higher than intensity of the other thereof;
• a diffraction grating drive unit configured to adjust a rotation position of the diffraction grating within a range that light of a specified wavelength region of the plus side diffracted light and light of the specified wavelength region of the minus side diffracted light among diffracted light caused by the diffraction grating is selectively guided to the flow cell;
• an optical sensor configured to detect light emitted from the flow cell due to light guided to the flow cell from the diffraction grating;
• and
• a diffraction grating position adjustment unit configured to adjust the rotation position of the diffraction grating by controlling an operation of the diffraction grating drive unit in order to selectively guide one of the light of the specified wavelength region of the plus side diffracted light and the light of the specified wavelength region of the minus side diffracted light among the diffracted light caused by the diffraction grating.