Determination of Dimethylamine and Triethylamine in Hydrochloride Salts of Drug Substances by Headspace Gas Chromatography using Dimethyl Sulphoxide- imidazole as Diluent

Abstract

A simple, rapid, accurate and precise analytical method for determination of secondary and tertiary amines in hydrochloride salt form of drug substances in non aqueous medium, which does not require any derivatization, was developed by headspace gas chromatography. Dimethylamine hydrochloride and triethylamine hydrochloride were analyzed in metformin hydrochloride. The sample was dissolved in a vial containing dimethyl sulphoxide and imidazole. The vials were incubated at 100º, for 20 min. The syringe temperature was maintained at 110º. DB624 column with 30 m×0.32 mm i.d., 1.8 µm film thickness was used. The injector and detector temperature were 200° and 250°, respectively. The analytical program used was carrier gas (nitrogen) flow rate: 1 ml/min; injected gas volume: 1.0 ml; split ratio: 1:10; oven temperature program: 40º for 10 min, followed by an increase up to 240° at 40º/min. The analytical method was validated with respect to precision, recovery, limit of detection and quantification and linearity.