Studies on Secondary Amines in Foods

II. Differentiation and Quantification of Nitrosated Secondary Amines by Gas-Liquid Chromatography

Abstract

Volatile secondary amines in foods can be differentiated and determined as follows: The secondary amines in a food sample are extracted with trichloroacetic acid, the extract is distilled in vacuum under alkaline condition; the amines in the distillate are nitrosated with sodium nitrite in acid solution (at 30°C for 30min.); the nitrosamines formed are extracted with methylene chloride, being concentrated and subjected to determination by a gas chromatograph with a modified thermoionic detector.
Two different types of columns, Chromosorb W-25% PEG 6, 000, and Chromosorb W-24% Versamid 900, both of which being packed in coiled glass tubings (3×2, 500mm), are employed_for gas-liquid chromatography, and the former column is suitable for the quantitative analysis of nitrosated secondary amines.
The recoveries of secondary amines added to foods were found more than 95%. The presence of primary and tertiary amines in foods at natural level did not interfere the analysis significantly. The application of the procedure to the analysis of salted Alaska pollack and fish ham samples disclosed that dimethylamine was the main component among the secondary amines in the materials so far tested, and a trace amount of diethylamine was also detected.