| High performance liquid chromatography(HPLC) has been used as an important analysis detection method due to its many advantages, such as high separation efficiency, high sensitivity, fast analysis speed, work simplification and so on. Sample preparation also an important part of analysis detection. The combination of advanced sample preparation and HPLC has been widely applied in environment analysis, food analysis, pharmaceutical industry, biology, industry and other fields.The thesis includes two sections:review and research report. In the review section, the development and characteristics of HPLC was simply summarized. Firstly we focused on the application of HPLC in environment analysis and food analysis, then some sample pretreatment methods and their applications were detailedly remarked. The object and significance of this study were simply summarized. The research report section includes four parts:1. Development of a dispersive liquid-liquid microextraction method for the determination of sulfonamides residues in water samples by high performance liquid chromatographyA novel method for the determination of sulfanilamide(SAD), sulfadiazine(SDZ) and sulfamethazine(SM2) residues in water samples has been developed by using dispersive liquid-liquid microextraction (DLLME) coupled with high performance liquid chromatography by DAD detection. Parameters such as type and volume of extraction solvent and disperser solvent, concentration and composition of sodium chloride and pH were optimized. The analytes were extracted under optimized pretreatment conditions. Linearity in the concentration range of 1～1000 μg/L was obtained with regression coefficients ranging from 0.9997 to 0.9999 and LODs were between 0.07 and 0.25 μg/L. The developed method was applied to the determination of the sulfonamides in five different water samples. The spiked recoveries from 82.0% to 104.0% and the relative standard deviation(RSD) was less than5.9%(n=6).2. Development of a dispersive solid phase extraction coupled with dispersive liquid-liquid microextraction method for the determination of sulfonamides residues in chicken liver by high performance liquid chromatographyA novel method for the determination of sulfacetamide(SAM), sulfathiazole(STZ),sulfamethazine(SM2) and sulfamethoxypyridazine(SMP) residues in chicken liver has been proposed by using dispersive solid phase extraction-dispersive liquid-liquid microextraction method coupled with high performance liquid chromatography by DAD detection. Parameters such as type and volume of extraction solvent and disperser solvent, concentration and composition of sodium chloride and pH were optimized. In the DSPE-DLLME method,chicken livers were firstly extracted with 50mM phosphoric acid:MeCN (30:70),following cleaning up with the solid adsorbent.1mL liquid supernatant of the resulting extract with 750μL 1,2-dichloroethane were quickly added into a centrifuge tube containing 10 mL water.The analytes were extracted under optimized pretreatment conditions. Linearity in the concentration range of 0.006～4.00 mg/kg was obtained with regression coefficients ranging from 0.9988 to 0.9992 and LODs were between 0.0004 and 0.0084 mg/kg. The developed method was applied to the determination of the sulfonamides in chicken liver samples. The spiked recoveries from 70.2% to 91.4% and the relative standard deviation(RSD) was less than5.35%(n=6).3. Determination of pesticide residues in water samples using dispersive liquid-liquid microextraction based on solidification of floating organic drop by high performance liquid chromatographyA novel method for the determination of pirimicarb, carbaryl, paclobutrazol and tebuconazole residues water samples has been proposed by using dispersive liquid-liquid microextraction based on solidification of floating organic drop coupled with high performance liquid chromatography by DAD detection.100 μL of 1-dodecanol and 1 of methanol were used as extraction solvent and disperser solvent blending them together,then adding into the water samples.After the floated extraction solvent had solidified in an ice bath,it was dissolved with methanol. Parameters such as type and volume of extraction solvent and disperser solvent, concentration and composition of sodium chloride and pH were optimized. Under optimized pretreatment conditions.,linearity in the concentration range of 0.01～1000μg/L was obtained with regression coefficients ranging from 0.9995 to 0.9999 and LODs were between 0.00071 and 0.42μg/L. The developed method was successfully applied to the determination of the pesticide residues in water samples.4. Development of a dispersive liquid-liquid microextraction method for the determination of fluoroquinolones in vegetables by high performance liquid chromatographyA novel method using dispersive liquid-liquid microextraction(DLLME) has been developed for the extraction of three fluoroquinolones (FQs) from vegetables samples. Clean DLLME extracts were analyzed for fluoroquinolones using liquid chromatography. Some experiment parameters such as the type and volume of the extraction solvent and dispersive solvent and pH were examined and optimized. Under the optimum condition, the linear range of the three fluoroquinolones were 10～1000μg/kg, R2≥0.9941. The recoveries determined in spiked blank vegetables ranged from 73.7 to 118.2%. The proposed method has been successfully applied to analysis of residues of levofloxacin, norfloxacin and ciprofloxacin in vegetables samples with satisfactory results. |
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