Identification and Estimation of Histamine, Tryptamine, Phenethylamine and Tyramine in Soy Sauce by Thin‐Layer Chromatography of Dansyl Derivatives

Histamine, tryptamine, phenethylamine and tyramine in soy sauce were derivatized by reaction with dansyl chloride in acetone‐water (3:l). The dansyl derivatives were extracted with benzene, separated by TLC, and quantitated by measuring the fluorescence of each derivative. The average recovery for the entire procedure was 80% for histamine and over 87% for the other three amines. Tyramine was the chief amine found. The constancy of tyramine formation was demonstrated by its presence in measurable quantities in 12 of 15 soy sauce samples examined. The highest tyramine concentration (0.47 mg/ml) was found in a tamari soy sauce. The tyramine content averaged 0.18 mg/ml. Histamine, found in 10 of 15 samples, and tryptamine, found in only 5, averaged 0.1 mg/ml and 0.08 mg/ml respectively in the positive samples. Phenethylamine was not found in any of the 15 samples.