Sakai T
J Pharm Sci. 1979 Jul;68(7):875-7. doi: 10.1002/jps.2600680723.
A solvent extraction and spectrophotometric method for selective determination of berberine in pharmaceuticals is proposed. Berberine forms an ion associate with tetrabromophenolphthalein ethyl ester, which is extracted into ethylene dichloride. Secondary and tertiary amines and alkaloids are coextracted with the berberine and complicate the berberine determination. The absorbance of the secondary and tertiary amines and alkaloids into ethylene dichloride, however, decreases nearly to zero when the temperature is elevated from 25 to 60 degrees. Thus, berberine can be determined successfully in the presence of the secondary and tertiary amines and alkaloids by using thermochromaism.
提出了一种用于选择性测定药物中小檗碱的溶剂萃取分光光度法。小檗碱与四溴酚酞乙酯形成离子缔合物，该缔合物被萃取到二氯乙烷中。仲胺、叔胺和生物碱与小檗碱一起被共萃取，这会使小檗碱的测定变得复杂。然而，当温度从25℃升高到60℃时，仲胺、叔胺和生物碱在二氯乙烷中的吸光度几乎降至零。因此，利用热致变色现象，可以在仲胺、叔胺和生物碱存在的情况下成功测定小檗碱。
