Sample Pretreatment Technoligy Based On Solvent Sublation And Its Application On Analysis And Separation

Sample pretreatment technology is the backbone of modern analytical work. According to the research of sample pretreatment techniques, researchers can get good and accurate experimental results. Compared to continuously improve equipment and the development of new instruments, more research workers have studied the sample pretreatment technology. Solvent sublation is a kind of liquid-liquid extraction which use adsorptive bubble instead of oscillation. The bubble surface adsorb the surface active target compounds in aqueous phase. By the rising gas bubble, the target compounds were brought in the organic phase and dissolve in it. Compared with traditional liquid-liquid extraction and solid-liquid extraction, solvent sublation have the advantages of high recovery, high enrichment coefficient, low organic solvent comsumption, soft extraction process, simple instrument and operation, and large quantity of sample.In this thesis, solvent sublation and its application on the determination of polymer additives and the separation of water-soluble active components in natural product were studied in detail. Analytical methods of trace antioxidants, ultraviolet absorbers and phthalate esters in plastic beverage packaging were established. The separation method of conbination aqueous two-phase flotation with preparative liquid chromatography was established to separate and purify water-soluble active components in natural product for the first time. Using this method, Glycyrrhiza uralensis Fisch and Solanum Rostratum were studied. High-purity target compounds were obtained. The main research results were follows:1. By the condition optimization of solvent sublation and high-performance liquid chromatography, a novel pretreatment method for separating and concentrating antioxidants and ultraviolet absorbers from plastic beverage packaging was developed. The analytical method showed good precision and accuracy. This method got low LODs of 0.34-1.25 ng/mL and LOQs of 1.13～4.15 ng/mL, which were better than the previous reports. The mean recoveries were in the range from 88.73% to 107.65% at 20,30, and 40 ng/mL spiked levels, and the relative standard deviations (RSDs) were in the range of 2.16% and 10.55%.2. A novel trace analytical method, solvent sublation followed by gas chromatography-mass spectrometry, was established for the trace determination of twenty-two phthalate esters (PAEs) in palstic beverage. In the solvent sublation section, the optimal conditions were obtained. The trace analysis method showed good precision and accuracy, low limits of detection (LODs) of 1.6 ng/L-183.5 ng/L and limits of quantification (LOQs) of 3.56 ng/L ～ 511.21 ng/L. The LOD and LOQ values were better than the previous reports. The established method will be a good method for researching the migration behavior of PAEs from plastic packaging to food, and can be used to control the food safety and provide basic data for the development of new legislation.3. A feasible aqueous two-phase flotation (ATPF) and preparative high performance liquid chromatography (pre-HPLC) method was established. Under the optimal conditions of ATPF, the recoveries of liquiritin and glycyrrhizic acid were more than 93%and 88%, respectively. The purities of final products, liquiritin and glycyrrhizic acid, were 99.4%and 99.1%, respectively.The emulsification effect in ATPF process was discovered for the first time, and the significant influence on the recovery of target compounds was discussed in detail.4. By ATPF-pre-HPLC method, two main compounds were obtained from solanum rostratum. Under the optimal conditions of ATPF, the recoveries of two target compounds were more than 97% and 99%, respectively. The purities of final products were 98.1% and 99.5%, respectively. The two compounds were identified by1H NMR,13C NMR, LCMS-IT-TOF. Compund 1 is Hyperoside and compound 2 are the mixture of 3’-O-Methylquercetin 3-O-β-D-Galactopyranoside, Astragalin and 3’-O-Methylquercetin 3-O-β-D-Glucopyranoside.5. High-speed counter-current chromatography was successfully used for the separation of two main compounds from Solanum Rostratum. The purities were 93.48% and 93.52%, respectively. The two compounds were identified by1H NMR,13C NMR, LCMS-IT-TOF. Compund 1 is Hyperoside and compound 2 is the mixture of 3’-O-Methylquercetin 3-O-β-D-Galactopyranoside, Astragalin and 3’-O-Methylquercetin 3-O-β-D-Glucopyranoside. Compared ATPF-preHPLC with HSCCC, the purites of compounds by ATPF-preHPLC were higher than those by HSCCC. The ATPF-preHPLC method is more suiable than HSCCC in the separation and puification of water-soluble active components in natural product.