UV spectrophotometer (SHIMADZU - 2501pc)
The 2501 spectrometer is a basic instrument composed of a double beam which permits to analyze the reference and the sample simultaneity and a photomultiplier as detector.
The spectrometer UV is based on the principle of ultraviolet/ visible spectroscopy. This technique uses photon beam with UV- VISIBLE wavelength range (190-900nm). This beam could be absorbed by passing through a liquid or solid sample. The absorption depends on the structure of sample molecules. Indeed, molecules containing bonding and non-bonding electrons (n-electrons) can absorb energy in the form of ultraviolet or visible light to excite these electrons to higher anti-bonding molecular orbitals. The more easily excited the electrons, the longer the wavelength of light it can absorb. There are four possible types of transitions (π–π*, n–π*, σ–σ*, and n–σ*), and they can be ordered as follows: σ–σ* > n–σ* > π–π* > n–π*.