A method modified from AOAC Official Method 994.07 was tested on CWDGS samples. Samples were mixed with water and IS, and then washed with hexane as descried above. Then the de-oiled aqueous extract (10 mL) was loaded onto a Chem Elut S column. After 5 min equilibration, the column was eluted with 160 mL of MTBE. The MTBE eluent was collected and dried down to ~100 µL.