Studies On The New Methods For Determination Of Environmental Hormone Pollutants

Environmental hormone pollutants widely exist in the environment we lived, which would pose a threat to the sustaind living and proliferation of humans and animals, In recent years, the harmfulness of environmental hormone pollutants and the analysis and testing of these pollutants have been one of the hot topics. Therefore, an increasing attention has been paid to the research and development of new analytical methods with sensitivity, selectivity, simplicity and applicability.In this thesis, several new indicator reactions have been investigated, and new methods for determination of organic environmental hormones have been proposed based on the fluorimetric kinetic analytical techniques. In addition, two kinds of functional solid-phase extractants have been synthesized and their application to the selective separation and pre-concentration of heavy metal environmental hormone pollutants have been studied in detail. The major contents of this work are as follows.1. An inhibitory kinetic fluorimetric method is proposed for the determination of trace bisphenol A. The method is based on the inhibitory effect of bisphenol A on the redox reaction between potassium bromate and butyl rhodamine B in hydrochloric acid medium. The detection limit for bisphenol A is 0.005μg/mL, and the linear range for the determination is 0.08-0.88μg/mL. This method has been successfully used for the determination of bisphenol A in feeding bottle, false teeth and surface water.2. It is found experimentally that Rhodamine B can be oxidized by Fenton-like reagent, leading to the fluorescence quenching of Rhodamine B. This redox reaction was inhibited by Pentachlorophenol. Based on this observation, a new kinetic fluorimetric method is established for the determination of pentachlorophenol. It is further observed that the reaction system is more stable and the analytical sensitivity can be increased in the presence of EDTA. When the catalyst in Fenton-like regents are existing in the forms Fe(III), EDTA- Fe(III) and EDTA- Fe(II), the linear range for the determination are, respectively, 0.04-0.48, 0.012-0.48, 0.0024-0.08 and 0.02-0.24μg/mL; and the detection limit for pentachlorophenol are 0.0038, 0.00096 and 0.0008μg/mL, respectively. This new method has been used to determine pentachlorophenol in synthesized samples of mixed phenols and in environmental water samples with recoveries of 97.0-103.9%.3. A kinetic spectrofluorimetric method was investigated to measure the concentration of trace resorcinol. This new method is based on the inhibitory effect of resorcinol on the redox reaction between rhodamine B and potassium bromate in dilute aqueous sulfuric acid. The detection limit and linear range for the determination of resorcinol are 0.012μg/mL and 0.024-0.280μg/mL,, respectively. Trace of resorcinol can be determined directly by the proposed method without any pre-sepration process when phenol and many other phenolic compounds are present.4. A new solid-phase extractant, diphenylcarbazone - functionalized silica gel has been synthesized, and its physico-chemical property, separation and adsorption behavior have been investigated for nine kinds of heavy metal ions. It is shown that diphenylcarbazone-functionalized silica gel has quite good applications to the selective enrichment and separation of Hg( II), Cd( II), Zn( II) and Cu( II) from other metal ions at the optimized conditions.5. A micro-column packed with diphenylcarbazone functionalized silica gel was used for the solid-phase extraction on line and determination of mercury and copper in real samples by flow injection spectrophotometry. At the optimal conditions, the linear range and the detection limit are found to be 0.001-1.5 and 0.0009μg/mL for Hg(II), and 0.001-0.6 and 0.0008μg/mL for Cu(II), respectively. The proposed method was demonstrated to be simple, fast, selective, sensitive, low-cost and less pollution.6. Xylenol orange functionalized silica gel was synthesized as a new selective solid-phase extractant of Hg(II). This extractant can be used to separate and enrich Hg(II) from eight metal ions with similar characteristics. The maximum adsorption capacities and pre-concentration factor are 1.83×10^-2 mmol / g and 333, respectively. The new solid phase extractant is found to be stable in 1-6 mol / L HCl or H₂SO₄, and also in common organic solvents. No obvious change in its performance has been observed after the extractant was reused for 50 times or stored for eight months.