Abstract: Hyphenation of GC with Ion trap mass spectroscopy in tandem (GC-MS/MS) was applied to the simultaneous determination of 16 polycyclic aromatic hydrocarbons (PAH′s) in lake sediments.The dried sample with addition of pyrene D10 as recovery indicator was extracted with mixed solvent of dichloromethane and acetone (1+1 by vol.).The extract was evaporated to 1 mL passed through the silicagel/Al2O3 column and eluted with n-hexane,CH2Cl2-n hexane (3+7) mixture and methanol successively to separate saturated hydrocarbons,aromatic hydrocarbons and non-hydrocarbons.The eluate containing the aromatic hydrocarbons was concentrated to 1 mL and used for GC-MS/MS analysis after addition of benzoperylene D12 as internal standard.Under the prescribed condition,the 16 PAH′s were separated satisfactorily by GC within 40 min,and then determined by MS/MS.Values of DL (3S/N) found were from 0.03 μg·L-1 (for naphthalene) to 0.34 μg·L-1 for dibenzo(a,h) anthracene.Values of recovery found were ranged from 70%-90%.