The five basic components of ultraviolet visible spectrophotometer are introduced

Ultraviolet-visible spectrophotometer is a common analytical instrument in the analytical testing laboratory, which is used to determine the absorbance of the measured substance under a certain wavelength irradiation, so as to achieve qualitative or quantitative analysis of the substance.  Its basic structure is composed of light source, monochromator, absorption cell, detector and signal display system.  

1. Light Source  

The light source is a device that provides the incident light that meets the requirements. The light source commonly used in the visible region of the UV-visible spectrophotometer is a tungsten lamp, and the light source commonly used in the ultraviolet region is a hydrogen lamp or a deuterium lamp.  

1. Tungsten lamp  

Tungsten lamp is a commonly used visible light source, it can emit a wavelength of 325~2500nm continuous spectrum, of which the most suitable wavelength range is 320~1000nm, therefore, it can also be used as a near infrared light source.  When the electric energy heats the tungsten lamp to incandescence, the distribution of the light intensity emitted in each band changes with the filament temperature.  The temperature of the filament depends on the supply voltage.  Small fluctuations in the power supply voltage will cause great changes in tungsten light intensity.  Therefore, it is necessary to use a regulated power supply, tungsten lamp working voltage is 12V, you can also use 12V DC power supply.  The life of tungsten lamp can generally reach more than 10,000 hours.  

At present, many photometers use halogen tungsten lamps instead of tungsten lamps, such as 7230 type, 754 type spectrophotometers.  Tungsten halide lamps have high luminous efficiency and long service life.  

2. Deuterium lamp  

Deuterium lamp is a commonly used ultraviolet light source.  The wavelength range of the light emitted by it is 190~400nm, and the wavelength range used is generally 190~360nm, in order to ensure the stability of the luminous intensity, it is also necessary to use a regulated power supply.  The service life of deuterium lamps: domestic ones are generally 500 to 800 hours, imported ones are generally 1000 hours, and a few can reach 2000 hours.  

In recent years, lasers with high intensity and high monochromaticity have been developed for use as ultraviolet light sources.  Commercially available laser sources include argon ion lasers and tunable dye lasers.