光度法测定黄芪、红花和艾叶中草药中锰的含量

Photometric Determination of Manganese in 3 Traditional Chinese Medicines(Astragalus Membranaceus,Safflower and Leaves of Artemisia Argyi)

取3种中药(黄芪、红花或艾叶)样品用浓硝酸消解,并加浓高氯酸冒烟至近干,使溶液成清彻、透明溶体。按方法所述分别用稀盐酸或稀硝酸定容为25 mL,分取此样品母液置于25 mL容量瓶中,先在氢氧化钠碱性介质中,在沸水浴中加热5 min,借空气及溶解氧使锰(Ⅱ)氧化至锰(Ⅳ),然后在磷酸(2+1)溶液介质中使锰(Ⅳ)与二安替比林苯乙烯基甲烷(DABVM)试剂反应生成络合物,在540 nm波长处测定其吸光度。络合物的吸光度值与锰(Ⅱ)质量浓度在0.5～5.0 mg·L^(-1)范围内呈线性关系。以上述3种中药样品为基体,用标准加入法检测其回收率,测得回收率值在102.6%～104.0%之间,测定值的相对标准偏差(n=5)均小于4.5%。

Samples of the 3 TCM＇s were digested with conc. HNO3 and evaporated to near dryness with conc. HClO4 to obtain clear and transparent solution. An aliquot of sample solution was taken and manganese was determined by the diantipyryl benzenevinylmethane （DABVM） photometric method. Manganese（Ⅱ ） in the solution was first oxidized to Mn（Ⅳ） in an alkali medium by air and dissolved oxygen and by heating in a boiling water bath for 5 min, and then reacted with DABVM in H3PO4 medium （2＋1）. The ahsorbance of the colored complex formed was measured at 540 nm. Linear relationship between values of absorbance and mass concentration of Mn（Ⅱ ） was obtained in the range of 0. 5 - 5.0 mg · L^-1. Recovery was tested by addition of standard manganese solutions to samples of the 3 medicines and determined by the proposed method, results of recovery were found in the range of 102. 6%-104.0%, with values of RSD＇s （n=5） less than 4. 5%