UV-visible absorption spectroscopy A method for analyzing and determining the composition and structure of a substance by utilizing an absorption spectrum of a substance molecule against ultraviolet visible light. The method has the characteristics of high sensitivity, good accuracy, simple and convenient operation, good analysis speed and wide application. Its measurement wavelength ranges from 200 to 1000 nm. Principle: The electron energy level and vibrational energy level of a molecule are quantized only when the energy of the radiated photon is exactly equal to the energy difference between the two energy levels (the energy difference between the two energy levels is related to the structure of the valence electron in the molecule) ), the molecule can absorb energy. The structure of a certain molecule is determined, so a molecule can only absorb photons with a wavelength within a certain range. We can determine the knot of a molecule by measuring the wavelength range of the photons it absorbs. Structure. Molecular spectral characteristics: Molecular spectroscopy differs from atomic spectroscopy in that it is a continuous broad absorption band rather than a simple sharp line spectrum. The basic structure of the UV-visible absorption spectrometer generally consists of three parts: an optical system, a mechanical system, and an electrical system. application: UV-visible spectrophotometry has a wide range of applications in the qualitative analysis of organic matter, and is used in minerals for the study of minerals, semiconductors, natural products and compounds. UV-visible spectrophotometry relies mainly on the spectral characteristics of the compound, such as the number, position and shape of the absorption front, compared with the standard spectrum to determine the presence of certain genes. Although UV-visible spectrophotometry is a relatively common method, in some cases it cannot be used alone to identify an unknown compound, but it must be used in conjunction with other methods to achieve accurate analysis. Development of UV-visible spectrophotometry: miniaturization, portable, and intelligent.