Abstract: A sensitive, accurate and reproducible analytical method was developed and validated to quantify perfluorooctanoic acid (PFOA) and its salts  in the coating layer of nonstick pan. Scraped samples of 0.5 gram were directly extracted with acetonitrile using an accelerated solvent extractor at 175 ℃, 10.3 MPa for 20 min. After rotary evaporation concentration, the PFOA was derivatized with acetyl chloride and methanol at 65 ℃ for 60 min in an air-tight container. An HP-1 MS capillary column (30 m×0.25 mm, 0.33 μm) was used for the separation of the analyte. The procedure for the analysis of PFOA was based on gas chromatography interfaced to negative chemical ion mass spectrometry, operated in selected ion monitoring mode. Selected ions of m/z 312, 350, 378, 408, 428 were chosen for quantitation. The assay was linear over the range of 0-1000 μg/L, and the detection limit of PFOA was 5 μg/kg. The precision and recovery were assessed on four different concentrations (5, 20, 100, 500 μg/kg). The recoveries were in the range of 90.9%-96.2% and the relative standard deviations were 1.37%-6.37%. The procedure was applied to monitoring PFOA in the coating layer of nonstick pan from supermarket and no positive result was found.

Key words: accelerated solvent extraction （ASE）, coating layer of nonstick pan , perfluorooctanoic acid and its salts, gas chromatography/mass spectrometry (GC/MS)