Abstract:An internal standard HPLC method was established for simultaneous determination of 15 kinds of PAHs in spices by. The samples were dissolved in sodium hydroxide, extracted with acetonitrile, redissolved by n-hexane, cleaned and concentrated by the Florisil SPE cartridge, and determined by HPLC, with benzo [a] pyrene D12 being used as the internal standard. This method had a good linear relationship in the range of 0~100 ng/mL, with the detection limits of PAHs in Capsicum being 0.5~3.0 μg/kg and the limits of quantitation as 2.0~10.0 μg/kg. The limits of detection and limits of quantitation of PAHs in Zanthoxylum were 0.5~1.0 μg/kg and 2.0~3.0 μg/kg, respectively. When the spiked levels were 2.0, 10.0 and 50.0 μg/kg, the recoveries in the two spices were 60.58%~119.48% and 60.46%~119.24%, with the RSD (n=6) being 1.25%~9.61% and 1.10%~8.56%. The concentration of ΣPAHs in the five spices from high to low were : green Zanthoxylum (561.2 ųg/kg) > erjingtiao (448.8 μg/kg) > red Zanthoxylum (358.3 μg/kg) > shizhuhongi (353.6 μg/kg) > chilli (243.5 μg/kg). The more seriously polluted areas of Chongqing were Bishan, Jiangjin and Rongchang, with ΣPAHs being 721.5, 626.6 and 621.0 μg/kg, respectively. The more seriously polluted compounds in PAHs were phenanthrene, fluoranthrene and pyrene, with their average contents being 215.10, 80.25 and 75.35 μg/kg, respectively. The internal standard method established in this study has high accuracy and good repeatability, which is suitable for the determination of PAHs in spices.
