1.2 T magnetic fields) and the supernatant was discarded. The solution
of 5% (v/v) methanol was used to wash aptamer-MNPs for three
times. Then, 200 L of acetonitrile–water–acetic acid 0.1 M (95:4:1,
v/v/v) was added and vortexed for 15 min, for desorption of the target
from the sorbents. 100 L of eluent solution were taken and the
solvent was evaporated by a gentle stream of nitrogen gas. Finally,
the analyte was redissolved in 50 L of electrospray solution containing
methanol/acetic acid 0.1 M(99:1, v/v) and then injected into
the IMS system.