| Extraction and enrichment technology is significant to separation and sample pretreatment of biological active component. They have direct effect on the accuracy of result. At present, many novel methods have appeared beside the classical liquid-liquid extraction, such as Solid Phase Extraction (SPE), Solid Phase Micro-extraction (SPME), Liquid Membrane Extraction (LME), Microwave Assisted Solvent Extraction (MASE), Accelerated Extraction (AE), Liquid Phase Micro-extraction (LPME), Supercritical Liquid Extraction (SLE), et al. Based on the knowledge of the mentioned methods, this thesis make systematic researched in the aspect of Liquid Membrane Extraction, single drop liquid phase micro-extraction and liquid-liquid-liquid micro-extraction. Due to the suggestion of liquid membrane is based on the biological membrane, interfacial properties of biological active component have also been studied in this thesis.1. The recent progress of the extraction and enrichment methods and researches are reviewed.2. In this paper, the transport of theanine in emulsion liquid membrane system containing Aliquat-336 as a carrier, Shang-205 as a surfactant and Cl' concentration gradient between interior and exterior phase as driving force was studied. The various factors affecting extraction in emulsion liquid system were investigated and explained systematically. The suitable conditions and the best membrane formulation were established, amino acid was extracted and concentrated successfully.3. Transfer efficiency of fifteen kinds of amino acids through emulsion liquid membrane has been studied in this paper. Aliquat 336 was used as carrier. The result shows that the transfer efficiency of amino acids is greatly relative to the lipophilicity of the side-chain, the morelipophilic amino acids were, the higher transfer efficiency was obtained.4. A rapid method for the determination of ephedrine and methylephedrine in urine by liquid-phase microextraction (LPME) coupled with high performance liquid chromatography (HPLC) was developed. The experimental conditions of LPME, such as extraction solvent, extraction time, solvent volume, pH of feed solution and stirring rate were optimized. The linear ranged from 0.05 u,g/mL to 8.0 Hg/mL, the detection limits were 0.025 |ig/mL and 0.04jag/ml respectively, and the relative standard deviations (RSD) were lower than 8.5% for ephedrine and 7.0% for methylephedrine. With LPME, some substances in urine which interfere with the determination of ephedrine and methylephedrine were eliminated efficiently and the higher selectivity was obtained. The method was simple, fast, sensitive and with little solvent consumption and suitable for the determination of ephedrine and methylephedrine in urine.5. Basic studies on carrier-mediated transport as a mechanism to extraction ephedrine and methylephedrine by liquid-liquid-liquid microextraction are described in this paper. The analytes were first extracted from weak acidic aqueous sample (donor solution) through Di(2-ethylhexyl) phthalate (D2EHPA), and then back-extraction into strong acidic acceptor. The LPME conditions were optimized for achieving high enrichment factor of the analytes from aqueous samples, in terms of carrier concentration in organic phase, sample pH, stirring rate, extraction time, hydrochloride acid concentration and microdrop volume. Enrichment factor of more than 900 would be achieved for ephedrine and methylephedrine. With LPME, substances in urine which interfere with the determination of ephedrine and methylephedrine were eliminated efficiently and* satisfied linearitywere obtained with correlation coefficients better than 0.99. Detection limits were 0.01 g/mL and 0.005g/mL for ephedrine and methylephedrine respectively.6. The interfacial properties of rutaecarpine at the chloroform-0.5 mol/L Na2SO4(pH=11) liquid-liquid interface have been investigated at 303 K. By fitting the experimental data of the interfacial tension to Szyzkowski isotherms, the in... |
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