Multiwalled carbon nanotubes coated fibers for solid-phase microextraction of polybrominated diphenyl ethers in water and milk samples before gas chromatography with electron-capture detection

Determination of polybrominated diphenyl ethers (PBDEs) in environmental samples has raised great concerns due to the widespread use of PBDEs and their potential risk to humans. Solid-phase microextraction (SPME) is a fast, simple, cost-effective, and green sample preparation technique and is widely used for environmental analysis, but reports on the application of SPME for determination of PBDEs are very limited, and only a few publications dealing with commercial SPME fibers are available for extraction of PBDEs. Herein, we report a novel SPME method using multiwalled carbon nanotubes (MWCNTs) as the SPME fiber coating for gas chromatography with electron-capture detection (GC-ECD) of PBDEs in environmental samples. The MWCNTs coating gave much higher enhancement factors (616–1756) than poly (5% dibenzene–95% dimethylsiloxane) coating (139–384) and activated carbon coating (193–423). Thirty-minute extraction of 10 mL of sample solution using the MWCNTs coated fiber for GC-ECD determination yielded the limits of detection of 3.6–8.6 ng L−1 and exhibited good linearity of the calibration functions (r2 > 0.995). The precision (RSD%, n = 4) for peak area and retention time at the 500 ng L−1 level was 6.9–8.8% and 0.6–0.9%, respectively. The developed method was successfully applied for the analysis of real samples including local river water, wastewater, and milk samples. The recovery of the PBDEs at 500 ng L−1 spiked in these samples ranged from 90 to 119%. No PBDEs were detected in the river water and skimmed milk samples, whereas in the wastewater sample, 134–215 ng L−1 of PBDEs were found. The PBDEs were detected in all whole fat milk samples, ranging from 13 to 484 ng L−1. In a semiskimmed milk sample, only BDE-47 was found at 21 ng L−1.