Study On High Performance Capillary Electrophoretic Method For Food Safety Analysis

Capillary electrophoresis (CE) is an important analytical tool and is underrapid development in the fields of food, medicine, pharmacy, biology and environment,for the advantages of its automation, fast and highly efficient separation and low reagentcost. Nowdys more and more people pay attention to the safety of food, so the methods tomonitor the quality of food are necessary and of great importance. In this thesis, some CEmethods were built for determination of compositions in food and medicine.In chapter1, the development history, basic theories, various separation modes,sample preparation and on-line preconcentration techniques of CE are briefly introduced.The various applications of CE in different food analysis have also been specificallystated.In chapter2, a CZE method for the determination of NEO in non-alcoholic beveragewas developed combined with solid-phase extraction. Optimum separation conditionsachieved were20mmol L-1sodium borate buffer with pH8.0, UV detection at191nm,25kV applied voltage and5s hydrodynamic injection at30mbar. Calibration curve showedgood linearity (R2=1.0000) in the range of0.5-100μg mL-1and the limit of detection was0.118μg mL-1. The method was successfully applied to the determination of neotame intwo kinds of beverage with migration time less than5min, relative standard deviation (n=3) less than2%and recoveries ranging from90%to95%.In chapter3, a simple CE method based on solid-phase extraction (SPE) for theanalysis of6-Benzylaminopurine (6-BAP) was established. Optimum separationconditions obtained were20mmol L-1sodium phosphate buffer, pH2.0,25kV appliedvoltage and UV detection at274nm. Amiloride hydrochloride (AM) was used as aninternal standard. Under optimum conditions, electrophoretic analysis was completed inless than7min, with LOD and LOQ of19and65ng mL-1for6-BAP. The method wassuccessfully applied to determine6-BAP in bean sprouts with the recoveries ranged from95.0%to103.4%and RSD lower than3.6%. Contrast experiments using HPLC method described in National Standards of People’s Republic of China were also carried out. Theresults validated of the two methods are comparable, but the proposed CE method wasfound to be simple, rapid, allowing separation and analyte quantification in shorter time,and the reagent consumption was reduced.In chapter4, a simple method has been established for the simultaneousdetermination of sibutramine and phenolphthalein by capillary electrophoresis. A mixtureof20mmol L-1phosphate buffer and20mmol L-1sodium dodecyl sulfate was used asrunning buffer (pH11.0). Analysis was carried out at a detection wavelength of223nmunder a separation voltage of25kV at20°C. The limits of detection (LOD, S/N=3) were0.05μg mL-1for sibutramine and0.2μg mL-1for phenolphthalein. The linearity of themethod was in the range of0.1-50μg mL-1for sibutramine and0.8-50μg mL-1forphenolphthalein. The proposed method has been successfully applied for thedetermination of the two target chemicals in functional foods, with satisfactory recoveryranged from95.3%-103.4%. The proposed method has been successfully applied for thedetermination of the two target chemicals in functional foods with satisfactory results.In chapter5, a rapid and sensitive method for the multiresidue analysis of threecommonly used pesticides in fruits and vegetables was developed by sweeping micellarelectrokinetic chromatography (MEKC). Parameters that affect the sweeping effciency inthe separation buffer were investigated and optimized. Under optimized conditions,imazalil、thiabendazole and thiophanate-methyl were completely separated within11minutes. The limits of detection (LODs) at a signal-to-noise ratio of10were0.230μgmL-1、0.195μg mL-1and0.244μg mL-1for imazalil、 thiabendazole andthiophanate-methyl, respectively. The proposed method has been successfully applied tothe analysis of the target residues in real samples with satisfactory results.