Extraction-Spectrophotometric Determination of Berberine in Pharmaceutical Preparations with 2, 6-Dichlorophenolindophenol

Abstract

A new application of monoacidic dye is reported for the determination of berberine. The method is based on solvent extraction into nitrobenzene of an ion-pair compound formed between 2, 6-dichlorophenolindophenol and berberine. Berberine is determined by measuring absorbance of the extracts over the range of (1-5)×10^-6M (0.408-2.04μg/ml) at 650 nm. The molar absorptivity was 3.8×10⁴l, mol^-1, cm^-1. Continuous variations plots have a maximum at 0.5 mol fraction of DCIP, indicating a 1 : 1 DCIP-berberine ratio.