The invention belongs to the technical field of environmental biological monitoring, in particular relates to an instrument and method for declassifying and discriminating algae based on chlorophyll analysis. The method comprises the following steps of : exciting chlorophyll of algae in a water sample to be detected to generate a characteristic absorption spectrum by adopting spectral analysis andutilizing a mixed dual beam light source for irradiation; and comparing with absorption wavelengths used for preselecting various algae according to variation of light intensity and wavelength of theabsorption spectrum to distinguish algae so as to classify and discriminate the algae. In the method provided by the invention, the chlorophyll contained in the algae in the water body is excited to generate a secondary excitation fluorescent light by virtue of irradiation of an external exciting light, and the algae can be rapidly and simply classified and discriminated according to the variation of the light intensity and the wavelength of the exciting light as well as the variation of the light intensity and wavelength of the secondary excitation light.
修改评论