Apple Polyphenols By Hplc Method

Seven neutral phenolic compounds and two phenolic acids in apples were determined by reversed phase high—performance liquid chromatography in this paper. According to the diversity between the neutral phenolic compounds and the acid polyphenols, they are separated with different mobile phase, at different column temperature and different wavelength of detector. After optimizing the chromatographic conditions of the phenolic standards (namely seven neutral phenolic compounds and two phenolic acids), the chromatographic separation was carried out using mobile phase methanol as solvent A and 2mM phosphoric acid as solvent B on C₁₈ column. The apples were divided into three parts of the skin, pulp and core according to the human edible habit. In order to avoid extracting the carbohydrate in apples, polyphenols in apple samples were extracted by ethylacetate. Phenolic acids were extracted at pH = 2 by ethylacetate and neutral phenolic compounds were extracted at pH =7 from their solution. The contents of polyphenols in FuJi apples and in XiaoGuoGuang apples were determined by this HPLC method. The result will be helpful to empolder the apples. The results are as following:1. For neutral phenolics, the gradient is a sequence of linear increments: starting with -2% methanol to reach 60% in 60 minutes, and 2mM phosphoric acid was changed from 98% to 40%. An additional flow rate gradient was included to achieve the better separation effects. A wavelength of A. =280nm was used for the detector.2. Phenolic acids were analysed in isocratic mode, at 1.0ml/min,using 70% methanol and 30% 2mM phosphoric acid as the mobile phase .The column temperature was 25℃, phenolic acids were quantified at 320nm. Resolution was 2. 5 .3. The detection limit were 0.022—0.072μg, the recovery rate were all...