Keywords: 
• polyfluorinated alkyl compounds /
• GC-MS /
• analysis method /
• pretreatment method

Abstract: The present paper described a method to measure seven volatile polyfluorinated alkyl substances by GC-MS. The target compounds included 6∶2 and 8∶2 fluorotelomer alcohols (FTOH), perfluoro-1-octanesulfonamide, N-methyl and N-ethyl perfluoro-1-octanesulfonamide, and N-methyl and N-ethyl perfluoro-1-octanesulfonamide ethanol. These chemicals were separated by gas chromatography and detected by positive chemical ionization mass spectrometry (GC/PCI-MS). 7∶2 secondary fluorotelomer alcohol was used as internal standard to calibrate the injection volume and instrument response variance. The chemicals were well separated by the column under the optimized conditions. The detection limits of the instrumental method (defined as S/N=3) ranged from 0.20 to 2.20 μg·L-1, and the limits of quantification (defined as S/N=10) ranged from 0.72 to 7.44 μg·L-1. The linear correlation coefficients of calibration curves were between 0.991-0.997. The relative standard deviations of 10 μg·L-1 standard mixture were between 3.14%-11.4%. Water and sediment samples were extracted with ethyl acetate, and purified by Envi-Carbon. Mass labeled 8∶2 fluorotelomer alcohol and N-ethyl-d5-perfluoro-1-octane- sulfonamide were spiked into sediment and water as surrogate standards to calibrate the recovery. The result showed that the recovery of the target compounds in sediment and water ranged 69.9%-135.8% and 64.3%-98.4%,respectively. The method detection limit and quantification limit were 0.25-2.75 ng·L-1 and 0.9-9.3 ng·L-1 for 400 mL water, and 0.10-1.10 ng·g-1 and 0.36-3.72 ng·g-1 for 1 g sediment, respectively.