Abstract
A singly charged tetrabromophenolphthalein ethyl ester (TBPE) was found to be extracted with quinine ethylcarbonate as a 1 : 1 complex in 1, 2-dichloroethane. Among various solvents, TBPE-1, 2-dichloroethane system gives the red colored species for alkaloids and amines, while in the absence of alkaloids and amines, the organic phase shows pale yellow color. In this way, the spectrophotometric method was investigated for the determination of a small amount of quinine ethylcarbonate by solvent extraction. Quinine ethylcarbonate is determined by measuring absorbance of the extracts over the range of 2×10-6 M to 1.6×10-5 M (0.793-6.34μg/ml) at 555 nm. From the electric conductivity measurements, the extracts with TBPE are classified into four categories as follows ; (1) blue ; dissociated ion-pair complexes (2) blue ; associated ion-pair compounds (3) red ; associated charge transfer complexes (4) yellow ; associated H·TBPE.
