Determination of Triethylamine, Pyridine and Dimethyl formamide content in Telmisartan by Headspace Gas chromatography using Flame Ionization Detector

Triethylamine, pyridine and dimethyl formamide are used as solvents in the synthesis of telmisartan. A simple, accurate and precise analytical method for determination of triethylamine, pyridine and dimethyl formamide in telmisartan was developed on headspace gas chromatography. The sample was dissolved in N-methyl pyrrolidone. Headspace vials of standard size and volume of 20 ml capacity were used for the study. The vials were incubated at 100°, for 20 min. Injection volume of headspace in to the gas chromatograph was 1 ml. The syringe temperature was maintained at 110°. The injector and detector temperature were 200° and 250°, respectively. Nitrogen gas was used as carrier gas with flow rate of 1 ml/min. Split ratio was 1:10. DB624 column with 30 m × 0.32 mm i.d., 1.8 µm film thickness was used. Column oven temperature was maintained at 40° for 15 min, followed by an increase up to 240° with the rate of 30°/min. The final temperature of the column with 240° was maintained for 5 min. This analytical method was validated with respect to precision, linearity, recovery, limit of detection and limit of quantification.