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目的:建立山核桃叶中总黄酮的含量测定方法。方法:以槲皮苷为对照品,采用AlCl3显色紫外分光光度法,结合单因素试验和正交试验对该体系进行系统优化研究,测定山核桃叶中总黄酮的含量。结果:AlCl3显色最佳条件为:2.0mL体系中加入pH4.7的HAc-NaAc缓冲液0.5mL,10%AlCl3醇溶液0.4mL,蒸馏水0.1mL,常温反应20min,416 nm处测定吸光度值。槲皮苷标准品含量在2.6～14.3μg.mL-1范围内与吸光度呈良好的线性关系(r=0.998),测得充分提取的总黄酮平均含量为5.89%,RSD为1.14%(n=3),平均回收率为99.1%,RSD为1.27%(n=6)。结论:AlCl3显色紫外分光光度法操作简便、准确、灵敏、重现性好,可用于山核桃叶总黄酮含量的测定。
Objective: To establish a method for determination of total flavonoids in pecan leaves. Methods: Quercetin was used as reference substance. The system was optimized by AlCl3 colorimetric spectrophotometry combined with single factor test and orthogonal test. The content of total flavonoids in pecan leaves was determined. Results: The optimum conditions for the color development of AlCl3 were as follows: 0.5 mL of HAc-NaAc buffer solution pH4.7, 0.4 mL of 10% AlCl3 alcohol solution and 0.1 mL of distilled water were added to the 2.0 mL system. The absorbance values were measured at 416 nm at room temperature for 20 min. The content of quercetin standard showed a good linear relationship with absorbance in the range of 2.6 ~ 14.3μg.mL-1 (r = 0.998). The average content of total flavonoids was 5.89% and the RSD was 1.14% (n = 3) with an average recovery of 99.1% and RSD of 1.27% (n = 6). Conclusion: AlCl3 chromogenic UV spectrophotometry is simple, accurate, sensitive and reproducible. It can be used to determine the content of total flavonoids in pecan leaves.