AMPEROMETRIC TITRATION OF PIPERAZINE SALTS AND THEIR PREPARATIONS

Piperazine salts (citrate and .phosphate) in 0.3 M citric acid solution form red crystalline precipitates with KBiI₄. The solubility of the precipitate as determined by polarographic method is 2.5×10^-4 M/l (18℃). An amperometric titration method for the determination of piperazine salts and their preparations is proposed as follows: Samples equivalent to 35—80 mg of piperazine are transferred to a 100 ml volumetric flask with 50ml of 0.6M citric acid, and 2g of KI are added. With continuous shaking, 20.00 ml of 0.12 M KBiI₄ are added and the reaction mixture is diluted with H₂O to the mark. After standing for 10 minutes, 10.00 ml of the clear supernatant solution are measured out and placed into a 150 ml beaker, then add to it 90 ml of 0.1 M citric acid-0.2 M sodium citrate solution, a crystal of Na₂S₂O₃ and 1 ml of 0.5% gelatin solution. After bubbling in clean inert gas for 15 minutes, the solution is titrated with 0.05 M EDTA. Current measurements are made at -0.5 V vs S.C.E. This method possesses a relative standard deviation not exceeding ±0.5%.