Colorimetric determination of piperazine in pharmaceutical formulations
Piperazine can be satisfactorily determined in pharmaceutical preparations or formulations such as effervescent granules and elixirs containing hexamine, colchicine, atropine sulphate, sodium benzoate, lithium benzoate, lithium citrate, sodium citrate, sodium hydrogen carbonate, tartaric acid, citric acid, lactose, sucrose and Tinct. ammi visnaga. The diluted sample solution is treated with a 0·6 per cent. aqueous 1,2-naphthoquinone-4-sulphonate solution in the presence of acetate-citrate buffer at pH 7·5. The temperature of the reaction should be between 10 and 15 °C and the colour produced is measured at 490 nm.