Determination of 4 Polycyclic Aromatic Hydrocarbons in Plant Extract by GC-MS Combined with Sulfuric Acid Acidifaction

The sample (5.000 g) was extracted ultrasonically with 25 mL of cyclohexane for two times, then the extract was concentrated to 5 mL and was acidized with sulfuric acid (80+20) solution. After being filtred by 0.2 μm filter membrane, the solution was separated on a HP-5MS chromatographic column. Electron impact ion source and selected ion monitoring mode were adopted in MS analysis. Linear relationships were found between the peak areas and the mass concentrations of 4 polycyclic armatic pydrocarbons in definite ranges, with detection limits in the range (3S/N) of 0.13-1.0 μg·kg^-1. Recovery rates obtained by standard addition method ranged from 84.2% to 105% and RSDs (n=6) ranged from 1.4% to 3.9%. The method was applied to analysis of 10 plant extracts, giving total mass ratio of 4 polycyclic aromatic hydrocarbons in the range of 19.59-142.69 μg·kg^-1.