分析化学
Print ISSN : 0525-1931
ピクリン酸によるベルベリンの溶媒抽出吸光光度定量
酒井 忠雄
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1978 年 27 巻 7 号 p. 444-447

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This paper deals with an extraction-spectrophotometric method for the determination of berberine in pharmaceuticals with picric acid (PCA). As shown in the previous paper, TBPE (tetrabromophenolphthalein ethyl ester) method has no selectivity because of the reaction with many onium compounds, in spite of having high sensitivity and stability. Therefore, DCIP (2, 6-dichlorophenolindophenol) method has been proposed on supplement of TBPE method for the depression of interferences of trace amounts of amines. However, DCIP has weak points on stability and effect of reagent concentration. On the other hand, this proposed method using PCA is excellent with respect to interferences, pH range and stability. Therefore, PCA method can supplement the former methods on various factors. The procedure is as follows; Phosphate buffer solution (pH 8) 5 ml, PCA solution (4×10-3 M) 2 ml and berberine standard solution (5×10-5 M) (15) ml are poured into a separatory funnel. After diluting the mixture to 50 ml with water, 10 ml of 1, 2-dichloroethane is added. After the solution is shaked for 3 min, the organic phase is centrifuged to remove droplets of water. The absorbance of the extracts is measured at 360 nm, using a reagent blank or water as a reference. Various inorganic or organic anions and cations do not interfere. However, only acrinol interfered slightly. Consequently, this method can be applied to the determination of berberine in pharmaceuticals containing many additions. The molar absorptivity is 4.0×104 mol-1 cm-1 l. The extracted species is presumed to be a 1:1 ion-pair compound between berberine and PCA.

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