Abstract: This paper describes an effective method for determining chlordiazepoxide. An excess of sodium tetraphenylboron is added to precipitate chlordiazepoxide in HAc-NaAc buffer solution (pH = 4.0). After filtering off the precipitate, the excessive sodium tetraphenylboron in the filtrate is titrated with cetyltrimethylammonium bromide standard solution, with bromophenol blue as indicator. The method is simple and rapid, it has been applied for the determination of chlordiazepoxide raw materials with satisfactory results. The recovery is between 99.58% and 100.4%, the relative error is less than ±0.50%. Experiments show that the method gives the same results as the approach using nonaqueous titration (ChP).

Key words: Chlordiazepoxide, Chlordiazepoxide, Sodium tetraphenylboron, Sodium tetraphenylboron, Bromophenol blue, Bromophenol blue, Cetyltrimethylammonium bromide, Cetyltrimethylammonium bromide