Pipette tip-based molecularly imprinted monolith for selective micro-solid-phase extraction of methomyl in environmental water

A novel low molecular weight methomyl molecule-imprinted monolith (MIM) was prepared inside a polypropylene pipette tip by polymerization reaction. Then the pipette tip-based MIM micro-solid-phase extraction (PT-MIM-mu-SPE) method was developed for selective extraction of methomyl in aqueous solution. The extraction parameters, such as the sample flow rate, sample volume and elution solvent, were investigated. By combining with a high performance liquid chromatography-ultraviolet detector, the PT-MIM-mu-SPE method showed a good linear range of 0.6-1000.0 mu g L-1 with a low limit of detection of 0.2 mu g L-1. The method was also applied for the pretreatment of methomyl in various environmental water samples. The relative recoveries were in the range of 84.9 to 105.1% with relative standard deviations less than 9.0%. The results showed that methomyl could be selectively enriched and monitored from environmental water samples.