Introduction of Instrument

UV-Visible spectrophotometer is an analytical instrument based on the principle of UV-Visible spectrophotometry, which uses the radiation absorption of material molecules in the UV-Visible spectral region to perform analysis.It is mainly composed of light source, monochromator, sample cell, detector and signal processor.The function of the light source is to provide a continuous spectrum of sufficient intensity and stability; deuterium lamps are usually used in the ultraviolet region, and tungsten lamps are usually used in the visible region; the function of the monochromator is to decompose the composite light from the light source and separate the monochromatic light of the desired wavelength from it.The measurement of the visible light region with a glass absorber cell, the measurement of the ultraviolet region shall use a quartz absorber cell; the function of the detector is to detect the intensity of transmitted light through the photoelectric conversion element, the light signal into an electrical signal.

Working Principle

Some groups in a molecule absorb UV-visible radiation light and undergo an electronic energy level jump to produce an absorption spectrum.Since the molecular composition, atomic composition and molecular space structure of different substances differ in their absorption of light energy, each substance has its own unique absorption spectral curve, and the substances are characterized or quantified according to the differences in characteristic wavelengths and absorbance of absorption spectral lines.The quantitative basis is the Lambert-Beer law.Lambert-Beer law equation: A = εbc, (A is the absorbance, ε is the molar absorbance coefficient, b is the liquid cell thickness, and c is the solution concentration).

Notices

1. After the power on to wait for the instrument self-test through, the light turns green after half an hour to warm up before testing.

2. In order to extend the service life of the filament please do not switch on and off frequently, the last student tested every day by the shutdown.

3. Absorbance close to 1 when the instrument is more sensitive, you can dilute the solution for measurement, the highest absorbance should not exceed 3 Abs.

4. Do not let the liquid spill on the instrument and inside the instrument to prevent damage to the instrument, if you accidentally spill the liquid, please wipe off in time.

5. When using the temperature control stirring attachment, please slowly increase the speed from low speed, if you quickly screw to high speed, the rotor can not operate normally. If the test temperature exceeds 40℃, please access cooling circulating water to protect the temperature control element; if the test temperature is lower than 15℃, please access N2 for purging, otherwise condensation will easily appear on the surface of the cuvette and affect the test results.

6. After the test, please put the desiccant into the test bin, if the discolored silica gel has completely changed color, please replace it in time.

7. Please make a reservation in the reservation register before use, and fill in the use register after use.

Explain: Sun Jingjing, 2020 master-Dai Linxiu team

Photograph: Li Xiujun, 2021 master-Li Xiao team

Montage: Li Xiujun, 2021 master-Li Xiao team