福林试剂光度法测定马占相思树叶中多酚含量

Photometric Determination of Polyphenols in Leaves of Acacica Mangium with Folin-Ciocalteu Reagent

采用福林(Folin-Ciocalteu)试剂光度法测定马占相思树叶提取液中多酚的含量。试样用乙醇(体积分数为60%)提取。分取部分提取液在加入福林试剂与100 g·L^(-1)碳酸钠溶液(1+9)的混合液20 mL,反应时间2 h,温度30℃的条件下进行显色,并于760 nm波长处测定其吸光度,以儿茶素为标样,多酚质量浓度在0.8～9.6 mg·L^(-1)范围内呈线性关系。在同一样品的萃取液中分取9份试液,分别加入儿茶素标准液,按方法操作求得方法的回收率为98.3%～102.9%。从同一试样萃取液中分取5份进行测定,求得其相对标准偏差为1.47%。

Leaves of acacica mangium was powdered and extracted with ethanol （φ60%）. An aliquot of the ethanol extract was reacted with a mixturecontaining 2 mL of the Folin-Ciocalteu reagent and 18 mL of 100 g · L^-1 Na2 CO3 solution for 2 h at 30 ℃. The absorbance of the colored solution was measured at the wavelength of 760 nm with 1 cm absorption cell against reagent blank as reference. Catachin standard solution （100 mg · L^-1 in absolute alcohol） was used as standard for polyphenol in preparation of standard curve. Range of linearity of the standard curve was kept between 0. 8 to 9.6 mg·L^-1. Precision was tested by determination of polyphenols in 5 portions of the extract from a same sample, value of RSD （n= 5） found was 1. 47% In the test for recovery, 8 different amounts of catachin standard were added to the same sample matrix and determined by the present method, values of recovery found were in the range of 98.3%-102. 9%.