A new simple, rapid and sensitive spectrophotometric method for the determination of chlordiazepoxide is described, based on the reaction with 2,4-dinitrophenol in water medium, apparently by a charge-transfer mechani...A new simple, rapid and sensitive spectrophotometric method for the determination of chlordiazepoxide is described, based on the reaction with 2,4-dinitrophenol in water medium, apparently by a charge-transfer mechanism, to yield 1:1 complex with maximum absorption at 444 nm. Optimum experimental conditions for the determination have been studied. The linear calibration range, apparent molar absorptivity and relative standard deviation are 2.8~96.0 mgmL-1, 1.48103 and 0.32%, respectively. The method is accurate and has been successfully applied to the determination of chlordiazpoxide in tablets. The results are in good agreement with those obtained with the official method.展开更多
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 p...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).展开更多
Polarographic catalytic wave of chlordiazepoxide in the presence of K 2S 2O 8 was studied in aqueous and DMF/H 2O mixed solutions. The results showed that a single reduction wave in alkaline medium was the reducti...Polarographic catalytic wave of chlordiazepoxide in the presence of K 2S 2O 8 was studied in aqueous and DMF/H 2O mixed solutions. The results showed that a single reduction wave in alkaline medium was the reduction of the N=C bond in 1,2 position of chlordiazepoxide via an intermediate free radical in two one electron successive additions. When K 2S 2O 8 was present, the free radical of the N=C bond was oxidized to regenerate the original, producing a parallel catalytic wave of chlordiazepoxide. It was determined that the apparent rate constant k f of the oxidation reaction was 3.2×10 3 mol -1 ·L·s -1 . Using the catalytic wave the trace of chlordiazepoxide can be determined by linear potential scan polarography. In NH 3/NH 4Cl (pH 10.2±0.1, 0.12 mol/L)/K 2S 2O 8 (0.016 mol/L) supporting electrolyte, the second order derivative peak current of the catalytic wave was rectilinear to chlordiazepoxide concentration in the range of 3.20×10 -8 -1.60×10 -7 , 1.60×10 -7 -1.44×10 -6 and 1.44 ×10 -6 -1.44×10 -5 mol/L, respectively. The limit of detection was 9.0×10 -9 mol/L.展开更多
文摘A new simple, rapid and sensitive spectrophotometric method for the determination of chlordiazepoxide is described, based on the reaction with 2,4-dinitrophenol in water medium, apparently by a charge-transfer mechanism, to yield 1:1 complex with maximum absorption at 444 nm. Optimum experimental conditions for the determination have been studied. The linear calibration range, apparent molar absorptivity and relative standard deviation are 2.8~96.0 mgmL-1, 1.48103 and 0.32%, respectively. The method is accurate and has been successfully applied to the determination of chlordiazpoxide in tablets. The results are in good agreement with those obtained with the official method.
文摘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).
文摘Polarographic catalytic wave of chlordiazepoxide in the presence of K 2S 2O 8 was studied in aqueous and DMF/H 2O mixed solutions. The results showed that a single reduction wave in alkaline medium was the reduction of the N=C bond in 1,2 position of chlordiazepoxide via an intermediate free radical in two one electron successive additions. When K 2S 2O 8 was present, the free radical of the N=C bond was oxidized to regenerate the original, producing a parallel catalytic wave of chlordiazepoxide. It was determined that the apparent rate constant k f of the oxidation reaction was 3.2×10 3 mol -1 ·L·s -1 . Using the catalytic wave the trace of chlordiazepoxide can be determined by linear potential scan polarography. In NH 3/NH 4Cl (pH 10.2±0.1, 0.12 mol/L)/K 2S 2O 8 (0.016 mol/L) supporting electrolyte, the second order derivative peak current of the catalytic wave was rectilinear to chlordiazepoxide concentration in the range of 3.20×10 -8 -1.60×10 -7 , 1.60×10 -7 -1.44×10 -6 and 1.44 ×10 -6 -1.44×10 -5 mol/L, respectively. The limit of detection was 9.0×10 -9 mol/L.
