The residues of dichlorvos and omethoate in the three woody plant species (Populus alba var bolleana, Sophora japonica and Malus pumilla), were extracted for the first time by means of the Supercritical Fluid Extraction (SFE) using carbon dioxide in this experiment. According to orthogonal experiments, the optimum conditions for co-extraction were 80C, 5000PSI, 18m1 of C02, with 750 ii hg modifier(methanol) added to the extraction cell, 25mm static and 30mm dynamic extraction with acetone, the l...