| Summary: | 碩士 === 國立宜蘭大學 === 食品科學系碩士班 === 97 === Chemical preservatives are commonly used in food products to prevent alteration and degradation by microorganisms during storage. However, excessive addition of these preservatives may be harmful to consumers. Therefore, the development of simple and rapid analysis methods of these preservatives is of great importance for food safety. The common analytical methods for preservatives in the food products are thin-layer chromatography, spectrophotometric method, gas chromatography, high performance liquid chromatography and capillary electrophoresis. Because of the advantages like the high separation efficiency, the short analysis time, the few sample volume needed, the simplicity of method development, the variety of application mode, and the complete instrumental automation etc... Therefore, capillary electrophoresis has become the important analysis method outside high performance liquid chromatography for preservatives.
This research establishes a capillary zone electrophoresis method with direct and indirect detection to simultaneously determine eight common used preservatives: acetic acid, benzoic acid, boric acid, dehydration acetic acid, methyl 4-hydroxybenzoate, propionic acid, sorbic acid and sulfite in food samples is performed by capillary zone electrophoresis with 0.5mM cetyltrimethyl-ammonium bromide (CTAB)－10mM 2,6-pyridinedicarboxylic acid (PDC) as background electrolyte at pH 10.8 and 25oC. The choices of the background electrolytes and the applied voltage were optimized. The effects of CTAB and pH on the separation were investigated in detail. Under the optimum condition, the linearity, reproducibility and detection limit of eight preservatives are shown, respectively. As an application of the method proposed, various samples of soft drink, vinegar, pearl sago, bread and dried Day Lily are analyzed to determine preservatives. The procedure described provides the advantages of good selectivity, recovery, rapid speed and simplicity for the separation and determination of preservatives.
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