GC-MS Determination of 12 PAHs in Sludge with Ultrasonic Assisted Extraction and Solid Phase Extraction

The sludge sample (about 1 g) was extracted ultrasonically for 1.0 h with 30 mL of mixed solution of ethyl acetate and acetone with volume ratio of 1:1. After centrifugation, the supernatant was taken and purified with solid phase extraction column of silicon. GC-MS was applied to the determination of 12 PAHs in the purified liquid. The HP-5MS quartz capillary chromatographic column was used for GC separation and the selected ion monitoring mode was adopted in MS determination. Linear relationships between values of peak area and mass fraction of the 12 PAHs were kept in the same range of 5-500 μg·kg^-1, with detection limits in the range of 2.29-14.50 μg·kg^-1. On the base of blank sludge sample, test for recovery was made by standard addition method; values of recovery found were in the range of 54.9%-108%, with RSDs (n=7) of determined values in the range of 0.10%-5.4%.