| A novel grapheme-based solid phase microextraction(SPME) fiber was prepared by coating graphene composite onto the surface of a treated copper wire using sol-gel method,and was applied in the direct determination of dioxin-like polychlorinated biphenyls(DL-PCBs) in the environmental samples，combining solid phase microextraction-gas chromatography-electron capture detector(SPME-GC-ECD) technology.The parameters influencing the extraction and efficiency,including extraction temperature,extraction time,sample pH,salt concentration and desorption time,were optimized.Under the optimized conditions,the chromatographic peak areas obtained from the grapheme-based fiber extracting twelve DL-PCBs were averagely two times higher than those obtained from the commercial fibers such as 100 μm PDMS,75 μm CAR/PDMS,85 μm PA.The grapheme-based fiber showed good linearity for DL-PCBs in the range of 0.05-3.5 μg?L-1 with correlation coefficients higher than 0.99 except PCB169(r2=0.987 4).The limits of detection(LODs) were in the range of 4.7-8.8 ng?L-1.The relative standard deviations(RSDs) were 1.4%-8.1% for a single fiber and 2.4%-12.8% for fiber-to-fiber.The average recoveries of twelve DL-PCBs were in the range of 87%-120% with spiked levels of 0.5 μg?L-1 for DL-PCBs standard in the environmental water samples and 2 ng?g-1 in the environmental mud samples.The proposed method was simple,sensitive and rapid, and could be used for the detection of trace amount of DL-PCBs. |