Study On A Novel Separation And Enrichment Technique Using Liquid Membrane Coupled With High Performance Liquid Chromatography Analysis

Liquid membrane separation technology has exhibited excellent character on separating and enriching metal ions and organic contaminations in the wastewaters due to their fast mass transport, great selectivity, high separation efficiency, convenient processes, and easy automatization. Liquid membrane is also used to study the separation and extraction of amino acids and their derivatives, and the drugs from fermentation broth and the biological fluids, respectively. However, it is a just beginning study field for pretreatment in analytical chemistry with liquid membrane separation. There are few papers on study of the transport mechanism of bioactive substances through the liquid membrane according to the simulative biofilm character of liquid membrane. Investigations for the extraction of bioactive substances in the natural products using the liquid membrane, and for the separation and enrichment of the hydrophilic target compounds to improve their analysis sensitivity by using liquid membrane as the pretreatment method are also seldom found.The transport mechanism through the liquid membrane, the methods on separation, extraction and enrichment using the liquid membrane, and the analysis with high performance liquid chromatography of amino acids and several drugs have been studied in the present article. The novel liquid membrane systems with high selectivity and separation efficiency have been obtained. Aim at the event of synthetic colorants Sudan recently happened, the simultaneous extraction and determination on the water-soluble and fat-soluble synthetic colorants have been explored for resolving the qualitative and quantitative analysis problem of the water-soluble and fat-soluble synthetic colorants, and their simultaneous extraction and determination. The details are summarized as follows:1. The transport mechanism of amino acids through the liquid membrane has been investigated using the simulative biofilm character of the liquid membrane. The transport kinetics of L-isoleucine and L-phenylalanine, and the transport selectivity for 15 kinds of amino acids constituted protein through di(2-ethylhexyl) phosphoric acid-kerosene bulk liquid membrane were studied in detail. The results indicate that the transport kinetics of L-isoleucine and L-phenylalanine through the liquid membrane could be analyzed in the formalism of a reversible pseudo-first order reaction followed by an irreversible pseudo-first order reaction. The results demonstrate that the lipophilicity constant of amino acid side-chain, the fraction of the protonated amino acid in the feed solution, and the complex ratio of amino acid-carrier complex are main factors for affecting the transport efficiency of the amino acid. The corresponding results are helpful to understand the transport behavior of amino acid inthe cell membrane of the organism.2. The new technique of liquid membrane separation in extraction of bioactive substances in natural products is presented in this thesis. The selective separation and extraction of rutaecarpine from E. rutaecarpa var. officinalis with the bulk liquid membrane and that of theanine from the tea water with tricaprylmethylammonium chloride-kerosene emulsion liquid membrane have been explored, respectively. The optimal separation conditions for the liquid membrane have been obtained. The results indicate that high recovery efficiencies were observed with proper values (0.718-1.03) of the partition ratio of rutaecarpine in the organic phase and the feed solution. The transport selectivity for 14 kinds of amino acids constituted protein through the liquid membrane was investigated. The results demonstrate that the lipophilicity constant of amino acid side-chain and the complex ratio of amino acid-carrier complex are main factors for affecting the transport efficiency of the amino acid. The linear relationship of the transport selectivity of the amino acid through the liquid membrane and the lipophilicity constant of amino acid side-chain has been obtained. The lipophilicity constant of theanine side-chain has also been calculated.3. The novel technique of micro-liquid membrane separation, enrichment and high performance liquid chromatography analysis and its application in biological fluids have been carried out. High compatibility with the mobile phase of high performance liquid chromatography has been reached by selecting o-dibutyl phthalate as the organic extraction solvent. The simultaneous separation and analysis method of three kinds of local anaesthetics in human urine using two-phase liquid-phase microextraction-high performance liquid chromatography has been established. The linear ranges are 0.1-10.0 mg L"1. The detection limits are lower than 0.05 mg L"1. The intra-day recoveries of analytes range from 95.2% to 97.3% at a spiking level of 5.0 mg L'1. Additionally, simultaneous separation, enrichment and analysis of hydrophilic drugs, morphine and ephedrine, and hydrophobic drug of pethidine with liquid-liquid-liquid microextraction based on carrier-mediated transport combined with high performance liquid chromatography have been achieved for the first time. The linear ranges are 0.2-5.0 mg L'1 (0.1-5.0 mg L"1 for ephedrine). The detection limits are lower than 0.1 mg L"1. The inter-day recoveries of analytes range from 95.8% to 102% at a spiking level of2.0mgL'1.4. Simultaneous separation, extraction and high performance liquid chromatography-diode array detection-electrospray mass spectrometry analysis of water-soluble and fat-soluble synthetic colorants in foodstuff have been studied. The simultaneous extraction and determination of water-soluble and fat-soluble synthetic colorantshas been reached for the first time by selecting dimethylsulfoxide as the extraction solvent and by applying selected ion recording to acquire mass spectral data in positive and negative mode. The recoveries of the eight synthetic colorants range from 94.8% to 102% at a spiking level of 10 fig/g. Linearity of around three orders in the magnitude of concentration was generally obtained and limits of detection for these compounds were in the range of 0.01-4 ng-...