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应用亚硝酸钠-硝酸铝-氢氧化钠体系分光光度法测定核桃花青皮中总黄酮含量时受到共存的胡桃醌和焦性没食子酸的明显干扰,经试验,提出了消除此干扰的校正方法。从乙醇提取液中移取两份等量试液(2.0mL),分别置于25mL容量瓶中,其中一份按方法加显色混合液,以试剂空白为参比,在波长508nm处先后于15,25min测其吸光度A1及A2;另一份中加乙醇(1+1)溶液13mL及40g·L-1氢氧化钠溶液10.0mL,摇匀,测其吸光度A0。根据所推导的公式计算总黄酮的吸光度,代入回归方程计算其含量。按改进的方法分析3份样品,测定值的相对标准偏差(n=6)在0.76%～1.3%之间。加标回收试验的回收率在89.0%～105%之间。
The interference of juglone and pyrogallol by coexistence was observed when the content of total flavonoids in walnut green peel was determined by sodium nitrite-aluminum nitrate-sodium hydroxide system spectrophotometry. The correction method to eliminate this interference was proposed through experiments. From the ethanol extract two equal parts of the test solution (2.0mL), were placed in 25mL volumetric flask, one by method plus color mixture, the reagent blank as a reference, at a wavelength of 508nm at 15,25min measured absorbance A1 and A2; the other with ethanol (1 + 1) solution 13mL and 40g · L-1 sodium hydroxide solution 10.0mL, shake, measured absorbance A0. Calculated according to the formula of total flavonoids absorbance, into the regression equation to calculate its content. Three samples were analyzed by an improved method with relative standard deviations (n = 6) between 0.76% and 1.3%. Spike recovery test recovery was between 89.0% ~ 105%.