Optical Property Of Chlorophyll And Its Application

The porphyrin and metal porphyrin exist extensively in the nature and the living body, such as all of cell dye, hemoglobin, chlorophyll...etc. Porphyrins are aromatic compounds comprising a large 20-membered aromatic ring and they can act as ligands, coordinating to a wide variety of metal ions via four nitrogen atoms. The porphyrin with a porphyrin ring has special structure and function and has been applied in chemistry, material science, medical science, biochemistry,and synthesizing realms. The chemistry of porphyrins has been extensively studied for many years in relation to the naturally occurring tetrapyrrole macrocyclic compounds in various biological systems. Recently, synthetic porphyrins have attracted attention in relation to the chemical and biological recognition. A large number of porphyrins receptors have been designed for the detection of biologically and environmentally important small species,for example simple inorganic cations or anions.The chlorophyll is one kind of the porphyrin, there is important function in the plant photo-synthesis and the mankind the life progress.The people's research toward chlorophyll has been the topic that people concern very much. This dissertation mainly consists of the separation of chlorophyll,optical property and its application. 1. A new method of extraction chlorophyll from fresh spinach leaves has been established by using column chromatography. The chlorophyll-a and chlorophyll-b are separated from fresh spinach leaves by the column chromatography with the sucrose as immobile phase and ether-petroleum (1:9v/v)as mobile phase. The chlorophyll-a was treated by HClO4 solution, the color of the solution quickly changed from blue green to dark and brown, showing pheophytin a was formed. If a few chlorophyll-a was dissolved in aether and then dropped on surface of water. After vaporizing aether the microcrystal chlorophyll-a could be obtained from the surface of the water. A ultraviolet visible spectrophotometer (UV-vis) was used to investigate the absorption characteristics of chlorophyll-a, chlorophyll-b, pheophytin-a,and microcrystal chlorophyll-a.2. Photofluorescence property of chlorophyll-a, chlorophyll-b, pheophytin-a,and microcrystal chlorophyll-a has been studied at room temperature. The chlorophyll concentration is fixed at 10-6 mol/L, the effects of dielectric constant, light, water and heat temperature, chlorophyll concentration, halogens anion,β–carotene on the fluorescence property of the chlorophyll-a, chlorophyll-b, pheophytin-a,and microcrystal chlorophyll-a. Photofluorescence property of chlorophyll-a, chlorophyll-b, pheophytin-a,and microcrystal chlorophyll-a was also affected by the exterior environment.3. Pheophytin-a(Pheoa) has been obtained by deintercalation of magnesium from the porphyrin ring of chlorophyll a(Chla) extracted from fresh spinach leaves. A fluorescence quenching phenomenum was observed when a copper(II)(Cu(II)) ion aqueous solution mixed with the Pheoa in an acetone solution. While similar concentrations of other physiologically relevant cations did not show this phenomenum. The effects of Cu(II) ion concentrations, reacting time and reacting temperature on the fluorescence intensity fading of the Pheoa solution have been investigated. An activation energy of 10.81 kJ mol-1 could be observed from Arrhenius empirical relation assuming the reaction between the Pheoa and Cu(II) ion obeys the first order kinetics to Cu(II) ion. The calibration graph obtained with the fluorescence was linear over the range of 2.0×10-5–8.0×10-7 mol dm-3 with a detection limit of 2.0×10-7 mol dm-3 for Cu(II) ion.