PURPOSE: To make the constitution of an optical system simple by storing preliminarily the photometric output when a sample is scanned at a specified wavelength, reading out the stored result in the stage of scanning at the other specified wavelength and calculating the same with the photometric value.
CONSTITUTION: Light of a single wavelength is made incident from a light source 1 through a spectroscope 2 to the sample on a scanning stage 3 and the light transmitted through or reflected from a thin film plate is detected with a photodetector 5 and is converted to an electrical signal in the stage of measuring the spectral absorbancy of the thin film plate in a thin film chromatograph. The electrical signal is stored in an RAM 9 after A/D conversion. The wavelength of the spectroscope 2 is then changed by means of a pulse motor 11 and the light of another single wavelength is made incident to the sample to obtain the photometric output. The photometric output is calculated by using the value stored in the RAM 9 and the noise component arising from the unevenness, etc. of the thin layer plate is removed from the measured result. the measurement of a two-wavelength method is thus accomplished by the simple constitution.
YAMAMOTO HARUO
NAKAMURA KENJI
