双水相超声萃取-分光光度法测定蒲公英中总黄酮

Spectrophotometric Determination of Total Flavonoids in Dandelion with Bi-aqueous Phase Ultrasonic Extraction

向50.0mg蒲公英粉中加入正丙醇2.00mL及磷酸二氢钠2.5g,于50℃进行双水相超声萃取30min。经过滤并静止分层后,黄酮进入正丙醇相中,使其与水相分离后,将正丙醇相蒸干,所得残渣用乙醇(1+1)溶液溶解定容至50mL,在510nm波长处测量其吸光度。黄酮的质量浓度在8.0mg·L^(-1)以内与其对应的吸光度呈线性关系。方法用于蒲公英中总黄酮的测定,测得萃取率达4.12%。

Total flavonoids in 50 mg of dandelion powder was ultrasonically extracted for 30 min from the medium containing 2.0 mL of n-propyl alcohol and 2.5 g of NaH_2PO_4.The flavonoids in the n-propyl alcohol phase,was separated and evaporated to dryness.The residue obtained was dissolved and made up to 50 mL with C_2H_5OH-H_2O（1 ＋ 1） solution,and its absorbance measured at 510 nm.Linear relationship between values of absorbance and mass concentration of total flavonoids was kept in the range of within 8.0 mg·L^（-1）.The proposed method was applied to the determination of total flavonoids in dandelion,with value of extraction rate achieved to 4.12%.