| Hunger breeds discontent, food in order to calm first. With economic development, there is growing concern about food safety issues. In this paper, the new analytical methods were developed for the determination of melamine residue, cyromazine (CM) and its metabolite in foods and feeds by capillary electrophoresis.Chapter one:The capillary electrophoresis technique was described simply. The analytical research and development status of melamine and cyromazine were reviewed.Chapter two:A novel solid-phase extraction-capillary electriophoresis (SPE-CE) method was developed for the determination of melamine residue in liquid milk. A 1% trichloriacetic acid plus 2.2% lead acetate solution were used for the extraction of analyte and the removal of protein. Study on the effects of pH, concentration of buffer, and voltage to the separation of the melamine. Under the optimized condition, the linearity is satisfactory in the range of 0.8-100 mg/L with a correlation coefficient of 0.9998. The method limit of detection (LOD) and method limit of quantification (LOQ) were 0.12 mg/kg and 0.37 mg/kg, respectively.Chapter three:A novel and simple method was, for the first time, developed for effective separation and sensitive detection of cyromazine (CM) and its metabolite melamine (MM) by capillary zone electrophoresis with diode array detection (CZE-DAD). Among different solvents, acetonitrile containing 20% NH40H was found to be the best one as an extractant of CM and MM in real samples. After centrifugation and filtering, the extract was analyzed by CZE directly. Examined sample handling methods, as well as buffer pH, concentration, voltage, temperature, etc. to optimize the working conditions of electrophoresis. Under the optimal conditions, The linearity is good in the range of 0.7-50 mg/L with correlation coefficient of 0.9998. The method limit of quantification (LOQ) for the two analytes was 0.38 mg/kg for feed samples and 0.42 mg/kg for egg and liquid milk samples. |
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