A spectrophotometer, also known as a spectrometer, is a scientific instrument that decomposes complex light components into spectral lines. The measurement range generally includes the visible light range of 380-780 nm and the ultraviolet light range of 200-380 nm. Different light sources have their own unique emission spectra, so different luminescent materials can be used as the light source for the instrument. The emission spectrum of tungsten lamp: The spectral light with a wavelength of 380-780nm emitted by the tungsten lamp light source can be refracted by a prism to obtain a continuous spectrum composed of red, orange, yellow, green, blue, indigo, and purple; This chromatography can be used as a light source for visible light spectrophotometers.

A spectrophotometer uses a light source that can generate multiple wavelengths. Through a series of spectroscopic devices, a specific wavelength light source is generated. After the light passes through the tested sample, some of the light is absorbed, and the absorbance value of the sample is calculated, which is then converted into the concentration of the sample. The absorbance value of the sample is directly proportional to its concentration. When monochromatic light radiation passes through a solution of the substance being measured, the amount absorbed by the substance is proportional to the concentration of the substance and the thickness of the liquid layer (optical path length), and the relationship is as follows:

A=-lg(I/I。)=-lgT=kLc