Difference between ultraviolet visible spectrophotometer and visible spectrophotometer

The difference between ultraviolet visible spectrophotometer and visible spectrophotometer is that the wavelength range is different Generally, hydrogen lamp is used for ultraviolet, the wavelength range is 180-350nm, and tungsten lamp is used for visible, the wavelength range is 320-1000nm The so-called UV-Vis spectrophotometer means that this instrument can replace the light source, and can determine the compounds with absorption peaks in the UV and visible parts If the absorbance is more than 2, it will no longer be displayed, which is a normal phenomenon Absorbance is the negative logarithm of light transmittance If the absorbance exceeds 2, it means that the light transmittance is less than 1%, which is lower than the detection limit of the instrument, it will no longer be displayed Whether you can use a spectrophotometer depends on the wavelength you measured Specifically, it can be divided into the following three points: 1 Different light sources: generally, the light source of visible spectrophotometer only uses tungsten lamp, while the ultraviolet visible spectrophotometer uses tungsten lamp + deuterium lamp as two light sources, and there are more switching parts of these two light sources This is because the spectral range of tungsten lamp is mainly in the near infrared region, and deuterium lamp is mainly in the ultraviolet region Because of the different light sources, there is also an extra deuterium lamp power supply for the UV-Vis spectrophotometer 2 Difference of optical devices: because glass can absorb ultraviolet wave and has better transmissibility to near infrared end, some optical parts of visible spectrophotometer can use glass, while ultraviolet visible spectrophotometer can't use glass parts, generally use quartz optical parts At the same time, because of this reason, the selection of cuvette is different The visible spectrophotometer can use the cuvette made of glass, while the ultraviolet visible spectrophotometer generally uses the cuvette made of quartz 3 Different receivers: because there are more UV waves in the UV-Vis spectrophotometer, the receiver selection is different With more sensitive response function to UV wave, the price of this kind of receiver is much higher than that of visible spectrophotometer.