Synthesis and evaluation of a molecularly imprinted polymer for selective on-line solid-phase extraction of 4-nitrophenol from environmental water

A molecularly imprinted polymer (MIP) able to bind 4-nitrophenol (4-NP) was prepared using noncovalent molecular imprinting methods and evaluated as a selective sorbent in molecularly imprinted solid-phase extraction (MISPE) on-line coupled to a reversed-phase HPLC. It has been shown that the condit ions chosen for washing the MIP and for eluting the analyte in the MISPE pr ocess are extremely important for ensuring good selectivity and recovery. R iver water samples, spiked with the 11 Environmental Protection Agency phen olic compounds at microgram per Liter levels, were preconcentrated on-line using this MIP, and 4-NP was selectively extracted. The humic acid interfer ence was simultaneously reduced considerably. The MTP was also compared wit h a commercially available highly cross-linked polymer (LiChrolut EN) and t he former yielded cleaner extracts.