Abstract
The concentration of 1-MTHBC, a precursor of harman, in several kinds of fermented seasonings commercially available in Japan was determined as a pentafluoropropionic acid derivative by gas chromatography with a flame thermionic detector and a capillary column. The contents of 1-MTHBC were 4-250ppm for soy sauce, 0.04-12ppm for mixed seasoning, 0.003-1.4ppm for miso and below 0.08ppm for vinegar. The correlations between the contents of 1-MTHBC and 1-MTHBC-3-carboxylic acid, ethanol or methanol in 23 brands of soy sauce were examined. As a result, a positive correlation between the contents of 1-MTHBC and methanol was found. To determine whether 1-MTHBC is originaliy present in soy sauce or is an artifact, 1-MTHBC in soy sauce was isolated by high performance liquid chromatography with an octadecyl silyl column and acidic aqueous solution/acetonitrile (1/1) as an eluant. It was canfirmed by mass spectrametry that 1-MTHBC detected in soy sauce was not an artifact.
