Ionic liquid molecularly imprinted polymers for application in pipette-tip solid-phase extraction coupled with gas chromatography for rapid screening of dicofol in celery

A new type of ionic liquid molecularly imprinted polymers (IL–MIPs) synthesized by precipitation polymerization using 1-allyl-3-methylimidazolium bromide as an auxiliary solvent and α-chloro-dichlorodiphenyltrichloroethane (α-chloro-DDT) as the template was applied as a selective sorbent of minimized pipette tip-solid-phase extraction (PT-SPE) for rapid isolation and extraction of dicofol (DCF) from celery samples. The pretreatment procedure of celery samples involved only 2.0   mg of IL–MIPs, 0.8   mL of acetonitrile–water (ACN–H 2 O; 1:1, v/v) (washing solvent), and 1.0   mL of acetone–10% acetic acid (HOAc) (elution solvent). Compared with molecularly imprinted polymers (MIPs), ionic liquid–non-imprinted polymers (IL–NIPs) and conventional sorbents such as C 18 , Si, NH 2 , and Al 2 O 3 –N, IL–MIPs showed higher adsorption and purification capacity to DCF in aqueous solution. Good linearity for DCF was observed in the range from 2.3 to 232.5   ng   g −1 ( r 2   =   0.9995). The average recoveries at three spiking levels ranged from 86.6% to 101.9% with relative standard deviations (RSDs) of ≤6.5% ( n   =   3). The presented IL–MIPs–PT-SPE–GC/ECD method combines the advantages of MIPs, IL, and PT-SPE, and can be used in aqueous conditions with high affinity and selectivity to analytes of complex samples.