Fig. 4
The recovery of five analytes spiked at 100 μg·kg−1 with different adsorbents. 150 mg of MgSO4 was mixed with 30, 50, 80, and 100 mg of C18, PSA and GCB, respectively, as adsorbents to complete the pre-treatment process, and the recovery was compared with determine the optimal adsorbent agent