| Sample preparation is a process for extracting, isolating and enriching the analytes of interest from sample matrices before analysis, which is time-consuming, labor intensive and greatly affects the accuracy and precision of method. Thus it becomes the bottleneck of the whole analysis process. In environment and pharmaceutical, especially Chinese traditional medicine analysis, the sample matrices are complex and the concentration of analyte is low. As a result of the co-extracted and co-eluted matrix compounds the signal of analyte may be enhanced or suppressed. Thus, the establishment of appropriate sample preparation methods is crucial. Recent trends in sample preparation are oriented towards use of smaller sample sizes, high-throughput performance, online coupling with various analytical instruments, automation, inexpensive operation and environmental friendly through reducing or eliminating organic solvents.Ionic liquid was successfully used in dispersive liquid-liquid microextraction progress and a new sample preparation methodology named reverse dispersive liquid-liquid microextraction which can deal with target analyte in organic phase was established. The results indicated that those methods were convenient, fast, accurate, sample-saving, environmental friendly and were validated for separation and quantification in pharmaceutical and environmental analysis. In this paper, three kinds of sample reparation methods were used in the determination of flavones, phenols and triterpenes, and five experimental systems were established. The main researches are as follows:1. Simultaneous determination of morin and quercetin in Fufang Yuxingcao Pian sample by ultrasonic extraction and reversed-phase high-performance liquid chromatographyA method for simultaneous ultrasonic extraction and determination of morin and quercetin in Fufang Yuxingcao Pian sample using reversed-phase high-performance liquid chromatography (RP-HPLC) was established. The optimum conditions for the extraction of morin and quercetin from Fufang Yuxingcao Pian sample were studied using orthogonal test, which included 50% ethanol as the extractant, ultrasonic temperature of 40-45℃, solid-liquid ratio of 1:20 (g/mL), ultrasonic time of 10 min, and twice ultrasonication. A Shim-pack VP-ODS column (150 x 4.6 mm,5μm) was used, the mobile phase was methanol-0.3% phosphoric acid (50:50), the detection wavelength was 260 nm and the flow rate was 0.7 mL/min. The calibration curve of morin was linear in the range of 0.8-100.0μg/mL with the correlation coefficient of 0.9998. The calibration curve of quercetin was linear in the range of 1.5-50.0μg/mL with the correlation coefficient of 0.9993. The method was convenient, rapid and accurate and was suitable for the simultaneous determination of morin and quercetin in Fufang Yuxingcao Pian sample.2. Simultaneous determination of phenols in Jialing river by ionic liquid based dispersive liquid-liquid microextractionIonic liquid was used in dispersive liquid-liquid microextraction progress to extract 2,4-dichlorophenol,2,4,6-trichlorophenol, bisphenol A,4-n-nonylphenol and 4-n-octylphenol in Jialing river. In this method,1.0 mL of acetone (disperser solvent), which contained 111μL of 1-hexyl-3-methylimidazolium hexafluorophosphate (extraction solvent), was added into the sample (5.0 mL). After shaking, a cloudy solution was formed. After centrifuging, the fine particles of l-hexyl-3-methy-limidazolium hexafluorophosphate are sedimented in the bottom of the conical test tube. And the sediment was directly injected into RP-HPLC for detection. Some important parameters, such as nature of ionic liquid, dispersing agent, ratio of ionic liquid and dispersing agent, effect of salt and pH were investigated. Analyte response was linear from 0.01 to 1.0μg/mL with the r values in the range from 0.9967 to 0.9993. The recovery of the method was in the range of 95.3-111.3%. The IL-DLLME method has the advantages of simplicity of operation, rapidity, low cost, high recovery and enrichment factor.3. Determination of oleanolic acid in Glossy Privet Fruit sample by ultrasonic-assisted extraction and reverse dispersive liquid-liquid microextractionA new microextraction technique termed reverse dispersive liquid-liquid microextraction was developed. An orthogonal array design was used to optimize ultrasonic extraction conditions. In this method, the appropriate chloroform (200μL) was injected into the sample (3.0 mL) by pipette. After shaking,7.0 ml of water was added and a cloudy solution was formed. In fact, it is consisted of fine particles of chloroform which was separated from ethanol phase. After centrifuging, the fine particles of chloroform are sedimented in the bottom of the conical test tube. The performance of reverse dispersive liquid-liquid microextraction (R-DLLME) was illustrated with the determination of oleanolic acid (OA) in glossy privet fruit sample by RP-HPLC. Some important parameters, such as volume of chloroform, water and extraction time were investigated. The optimized method exhibited a good linearity (r= 0.9997) over the studied range (10-200μg/mL) for oleanolic acid. The recovery was 98.0-108.5%. R-DLLME is a very simple and rapid method for the extraction and preconcentration of OA from Glossy Privet Fruit sample. The R-DLLME method has the advantages of simplicity of operation, rapidity, low cost, high recovery and enrichment factor.4. Determination of ursolic acid in Force Loquat Capsule by ultrasonic extraction and ionic liquid based reverse dispersive liquid-liquid microextractionIonic liquid was used in reverse dispersive liquid-liquid microextraction. An orthogonal array design was used to optimize ultrasonic extraction conditions. In this method, the appropriate ionic liquid (100μL) was injected into the sample (1.5 mL) by pipette. After shaking,2.5 mL of acidic water solution (pH 2.0) was added and mixed thoroughly, resulting in the formation of cloudy solution. After centrifuging, the fine droplets of ionic liquid were sedimented in the bottom of the conical test tube. The performance of ionic liquid based reverse dispersive liquid-liquid microextraction (IL-R-DLLME) was illustrated with the determination of ursolic acid (UA) in force loquat capsule sample by RP-HPLC. The optimized method exhibits a good linearity (r= 0.9989) over the studied range (2.0-60.0μg/mL) for UA. The recovery was 95.9-105.5%.5. Simultaneous determination of ursolic acid and oleanolic acid in Jacaranda mimosifolia by ultrasonic extraction and ionic liquid based reverse dispersive liquid-liquid microextractionUrsolic acid and oleanolic acid in the Jacaranda mimosifolia sample were simultaneously determined using ionic liquid based reverse dispersive liquid-liquid microextraction-reversed-phase high-performance liquid chromatography. An orthogonal array design was used to optimize ultrasonic extraction conditions. In this method,200μL of 1-octyl-3-methylimidazolium hexafluorophosphate was injected into 4.0 mL of the sample by pipette. After shaking, 9.0 ml of water was added and a cloudy solution was formed. After centrifuging, the fine particles of ionic liquid were sedimented in the bottom of the conical test tube. The influence factors on extraction efficiency, such as volume of ionic liquid, water and extraction time, were investigated. The optimized method exhibits a good linearity (r= 0.9999,0.9996) over the studied range (14.0-50.0, 4.0-50.0μg/mL) for UA and OA, respectively. The recovery was 83.4.9-106.2% and 98.3-101.4%, respectively. IL-R-DLLME is a new method for the extraction and preconcentration of UA and OA from Jacaranda mimosifolia sample with the advantages of simple, rapid, low cost, high recovery.
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