Selective solid-phase extraction of ethynylestradiol from river water by molecularly imprinted polymer microcolumns

A selective on-column molecularly imprinted solid-phase extraction (MISPE) for ethynylestradiol (EE2) from water samples was developed. Following a non-covalent molecular imprinting approach, two molecularly imprinted polymers (MIPs) have been synthesised using methacrylic acid (MAA) as functional monomer, ethyleneglycol dimethacrylate (EGDMA) as crosslinker and EE2 as template, in two different polymerisation solvents (acetonitrile or toluene). The optimisation of the on-column MISPE conditions for the selective rebinding of the EE2 resulted in a flow rate of 2.3 mL min(-1) and volumes of 1 mL toluene and 1.5 mL methanol-acetic acid (9: 1) for washing and elution steps, respectively. The selectivity of the imprinted polymer towards several related estrogens such as estriol (E3), estrone (E1) and estradiol (E2) was evaluated. The recovery of EE2 from a 50-mL spiked river-water sample was 75% when the optimised on-column MISPE was applied.