Determination of Six Polycyclic Aromatic Hydrocarbons in Fish Tissue by Isotope Dilution GC/HRMS

An isotope dilution mass spectrometry(IDMS) method for the determination of 6 polycyclic aromatic hydrocarbons(PAHs), including fluoranthene, benzobfluoranthene, benzokfluoranthene, benzoapyrene, benzog,h,iperylene, indeno1,2,3-c,d-pyrene, in freezing dried fish tissue was established. 6 PAHs were extracted with dichloromethane by soxhlet extraction under 50 ℃ for 18 h. Purification of extracts was carried out by gel permeation chromatography(GPC) and solid phase extraction(SPE). Dichloromethane was chosen as mobile phase after comparing the eluting effect of 6 PAHs with V(ethyl acetate)∶V(cyclohexane)=1∶1, and V(cyclohexane)∶V(dichloromethane)=1∶1 was chosen as eluting solution of SPE after optimizing the type and ratio of eluting solution. 6 PAHs were separated by capillary column DB-5(30 m×0.25 mm×0.25 μm) with helium as carrying gas. 6 PAHs were quantified by high resolution mass spectrometry multi-ion detection(HRMS-MID), using deuterated PAHs as internal standards, single point method. The recoveries of 6 PAHs are in the range of 95%—105%. The detection limits of 6 PAHs are 0.8—1.6 μg•kg^-1 (dry weight). The RSD(n=6) ranges from 1.7% to 6.0%. The methods was applied to three fish sample, the spectrum of the sample showed the little inference and ideal sensitivity of the method. With good sensitivity and accuracy, this method will be successfully applied to the qualitative and quantitative analysis of fish tissue sample.