Effect of commercial processing procedures on carbofuran residues in soybean oil

Dry seeds of soybean from 14C-carbofuran-treated plants contained about 1% of the originally applied radioactivity. Extraction of the seeds with hexane and methanol left 50% of the 14C in the cake. Analysis of residues showed the presence of free products in the oil and conjugated metabolites in the methanol extract. The free substances were identified as carbofuran and its phenol. The percentage of the latter increased during the successive refining processes. The refined oil had only 16% of the radioactivity originally present. The methanol extract contained four glucosides, mostly those of 3-hydroxy carbofuran. Refining soybean oil fortified with 14C-carbofuran reduced the residue in the oil by 78%. Most of the residue remaining was carbofuran.