THE SIGNIFICANCE TO HUMIFICATION OF DIFFERENT FORMS OF p-COUMARIC AND FERULIC ACIDS IN A POND SEDIMENT

Abstract

We studied the isolation of the three different forms, A, B, and C, in which p-coumaric and ferulic acids exist in a pond sediment, as well as their relative distribution, by gas liquid chromatography (GLC) and gas liquid chromatography combined with mass spectrometry (GLC-MS). The A form, designated as the free form, was isolated with hot ethyl acetate by repeated refluxing and is significant for allelopathic studies. The B form is a combined form that was extracted with hot ethyl acetate. The C form is another combined form; it was unextractable with hot ethyl acetate, but could be isolated with hot 2 M NaOH by repeated extraction. The C form appears to be bound to the sediment matrix and not to move easily in the environment. The content of p-coumaric acid in the A, B, and C forms was 0.41, 4.4, and 55 ±g/g sediment, respectively; that of ferulic acid was 0.07, 5.4, and 20 ±g/g sediment, respectively. A brief discussion of the possibility of another mode of humification involving the vinyl polymerization of both substituted cinnamic aids is also given. Additionally, we studied that of p-hydroxybenzoic and vanillic acids and compared the contents of the above four phenolic acids in the sediment with those of previous data for peat soil and forest soil.