Preparation of polypyrrole-coated magnetic particles for micro solid-phase extraction of phthalates in water by gas chromatography–mass spectrometry analysis

In this work, polypyrrole (PPy)-coated Fe3O4 magnetic microsphere were successfully synthesized, and applied as a magnetic sorbent to extract and concentrate phthalates from water samples. The PPy-coated Fe3O4 magnetic microspheres had the advantages of large surface area, convenient and fast separation ability. The PPy coating of magnetic microspheres contributed to preconcentration of phthalates from water sample, due to the π–π bonding between PPy coating and the analytes. Also, the coating could prevent aggregation of the microspheres, and improve their dispersibility. In this study, seven kinds of phthalates were selected as model analytes, including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-iso-butyl phthalate (DIBP), di-n-butyl phthalate (DBP), benzylbutyl phthalate (BBP), di-(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DNOP), and gas chromatography–mass spectrometry (GC–MS) was introduced to detect the phthalates after sample pretreatment. Important parameters of the extraction procedure were investigated, and optimized including eluting solvent, the amount of Fe3O4@PPy particles, and extraction time. After optimization, the procedure took only 15 min to extract and concentrate analytes with high efficiency. Validation experiments showed that the optimized method had good linearity (0.985–0.998), precision (3.4–11.7%), high recovery (91.1–113.4%), and the limits of detection were from 0.006 to 0.068 μg/L. The results indicated that the novel method had advantages of convenience, good sensitivity, high efficiency, and it could also be applied successfully to analyze phthalates in real water sample.