Before starting the extraction, the required amount of dry sorbent was weighed based on the number of samples and then washed. The tested suspension concentration ranged from 2 to 20 mg/mL and the suspension volume ranged from 600 to 1000 µL for a 200 µL sample volume. Suspension was vortexed to ensure homogeneity at every instance prior to sample addition. Plasma samples were prepared for each condition, with the inclusion of sham (prepared using sorbent-free solvent) samples and analyzed by C18 RPC+/-and C8 RPC+.