Selective trace enrichment of chlorotriazine pesticides from natural waters and sediment samples using terbuthylazine molecularly imprinted polymers

Two molecularly imprinted polymers were synthesized using either dichlorome thane or toluene as the porogen and terbuthylazine as the template and were used as solid-phase extraction cartridges for the enrichment of six chloro triazines (deisopropylatrazine, deethylatrazine, simazine, atrazine, propaz ine, and terbuthylazine) in natural water and sediment samples. The extract ed samples were analyzed by liquid chromatography/diode array detection (LC /DAD), Several washing solvents, as well as different volumes, were tested for their ability to remove the matrix components nonspecifically adsorbed on the sorbents, This cleanup step was shown to be of prime importance to t he successful extraction of the pesticides from the aqueous samples. The op timal analytical conditions were obtained when the MIP imprinted using dich loromethane was the sorbent, 2 mt of dichloromethane was used in the washin g step, and the preconcentrated analytes were eluted with 8 mt of methanol. The recoveries were higher than 80% for all the chlorotriazines except for propazine (53%) when 50- or 100-mL groundwater samples, spiked at 1 mu g/L level, were analyzed. The limits of detection varied from 0.05 to 0.2 mu g /L when preconcentrating a 100-mL groundwater sample. Natural sediment samp les from the Ebre Delta area (Tarragona, Spain) containing atrazine and dee thylatrazine were Soxhlet extracted and analyzed by the methodology develop ed in this work. No significant interferences from the sample matrix were n oticed, thus indicating good selectivity of the MIP sorbents used.