1985 Volume 1 Issue 3 Pages 275-279
Extraction-spectrophotometric determination of pilocarpine with copper(II) and tetrabromophenolphthalein ethyl ester(TBPE) has been developed. Pilocarpine reacts with copper(II) to form a 1:1 stable cationic complex that can be extracted with TBPE dye anion in an aqueous layer buffered at pH 9 into 1, 2-dichloroethane. Molar absorptivity of the ion associate is 1.8×104mol-1 cm-1 dm3 at 528nm and concentrations of copper(II) and TBPE for 1×10-5 mol dm-3 (2.4μg cm-3) pilocarpine are 2×10-4mol dm-3 and 3.2×10-4mol dm-3, respectively. This method can be applied to the determination of trace amounts of pilocarpine in an ophthalmic solution.
