Soil degradation of trifluralin: mass spectrometry of products and potential products.

The examination of soil which has been treated with trifluralin (TREFLAN alpha,alpha,alha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) has resulted in the identification of 28 degradation products. This paper presents the mass spectra of these products and a number of related compounds which were suspected products but were not found in trifluralin-treated soil. The mass spectra of the N,N-dialkylamines, with one exception, show major peaks due to amine alpha-cleavage and due to amine alpha-cleavage followed by carbon-nitrogen bond fission with rearragement of a hydrogen atom. Compounds having nitro groups yield mass spectra containing peaks due to intra-ionic oxidation by the nitro groups. In some cases, propionyl ions formed by this process are major ions in the spectra. Azo and azoxybenzenes resulting from condensation of two trifluraline moieties through nitro-nitrogens fragment mainly through the nitrogen-nitrogen bond.