Magnetic solid-phase extraction based on modified magnetic nanoparticles for the determination of phthalate diesters in water samples.

A method was developed for the extraction of phthalic acid esters (PAEs) from bottled water. Surface-functionalized magnetic particles (MPs) were used as adsorbent of magnetic solid-phase extraction (MSPE). The MPs were prepared by using both polydimethylsiloxane and multiwalled carbon nanotubes. By coupling the developed MSPE with GC-MS instrument, a reliable, sensitive and cost-effective method for the simultaneous determination of six main PAEs including dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), butyl benzyl phthalate, di-n-octyl phthalate and bis(2-ethylhexyl) phthalate (DEHP) was developed. Under optimized conditions, the LODs and limits of quantification were in the range of 0.01-0.025 and 0.025-0.05 µg/L, respectively. The calibration curves were linear (r(2) ≥ 0.992) over the concentration ranges from 0.05 to 20 µg/L. Based on the intra- and interday precision values with overall RSD ≤ 12.40%, the method reproducibility was adequate. The recovery values of the six PAEs ranged from 91.5 to 97.8% with the RSDs <10.64%. Finally, the developed method was successfully applied to determine PAEs in bottled water samples. DMP, DEP, DBP and DEHP were detected in most of the samples. Taken together, the developed MSPE-GC-MS method provides a new option for the determination of PAEs in aqueous samples.