The New Methods For Determination Of Chlorophenols Environmental Estrogens In Environmental Water

Chapter 1In order to establish new methods for the determination of trace chlorophenols environmental estrogens(CPs-EES) in environmental water by fluorescence quenching method , a reaction system of HSA-tris-HCl-CPs(2,4-DCP) was selected. The properties of the fluorescence quenching spectrum of the system was studied. The affecting factors on the strength of fluorescence quenching including acidity, dosage , temperature, reaction time, coexisting ions etc.,and the optimal conditions of the reactions in the system were investigated. A new method based on the linear relationship of the fluorescence quenching intensity (â–³F=F0-F) to the concentration of chlorophenols in solution was established in the system.The results showed that 2,4-DCP-HSA complex formed resulted in significant descend of intensity of fluorescence of HSA in the pH8.5 tris-HCl medium.The maximum fluorescence peak located at 344nm. The detection limit was 2.26×10-10g/mL and the linearity range were 0.75⁶.50 μg/10mL for 2,4-DCP. When the proposed method was used to determine CPs-EES (2,4-DCP) in environmental water, combined with solid phase extractor (SPE), the satisfactory results were obtained and the relative standard deviation was less than 2.91 % and the recovery range was 96.44% 105.94%.Chapter 2The characteristics of the association reaction of 2,4-DCP with HSA was studiedby fluorescence spectroscopy and absorption spectroscopy. It was foud that the fluorescence strength of HSA solution was greatly descend dy the interaction between 2,4-DCP and HSA at 344nm. The data of fluorescence quenching value were analyzed according to Stern-Volmer equation and linear regression equation, and the binding constant of the reaction, the binding distance and the basic thermodynamic parameters of the blinding process were obtained.The results show that the fluorescence quenching mechanism was a static quenching procedure by combining HSA with 2,4-DCP. The fluorescence quenching constant Kq was 3.71×10¹³L·mol-1·s-1, and the equilibrium constant was 2.74×106 L/mol. The number of binding sites was 1. It binds to Trp residue first but it result in any microenvironment changes of Trp residue. The binding distance between HSA and 2,4-DCP and energy transfer efficiency were 2.17nm and 0.292, respectively.Chapter 3The article focused on applying the surfactant to increase sensitivity of spectrophotometry for the determination of chlorophenols. In order to establish new methods for the determination of trace CPs-EES in environmental water by micelle-sensitized spectrophotometry. The new system of H2O2-4-AAP-ST-tris-HCl-CPs(2,4-DCP) was selected.The characteristics of the absorption spectra was studied. The affecting factors of the reaction system were investigated. The new method based on the linear relationship of the intensity of absorbency to the concentration of chlorophenols in solution was established in the system and a pilot study on the mechanism of reaction was given.The results showed that under the optimal conditions optimized through One-Factor Changing experiment, when reagent solution was used to refer compare, the system of H2O2-4-AAP-SDS-tris-HCl-2,4-DCP appeared the maximum intensity of absorbency at λmax=507nm in pH7.4tris-HCl medium. And the system had beter linear within 0.0226⁰.626 μg/mL and the determination limit was 6.78×10^-10g/mL...