| The analytical method for 16 USEPA priority polycyclic aromatic hydrocarbons(PAHs) in soil was optimized in this study,and an integrated quality control(QC) system was established to resolve the problems occurring in PAHs analysis,such as the lower recoveries of benzo(a)pyrene(BaP),unsatisfactory clean-up efficiency for samples in complex matrix,volatilization loss and environmental background of naphthalene(Nap) and phenanthrene(Phe).The analysis procedure commenced with accelerated solvent extraction(ASE),followed by solid phase extraction(SPE) clean-up and gradual condensation in vacuum.Gas chromatography-mass spectrometry(GC-MS) was used for measurement.Deuterated benzo(a) pyrene(BaP-d12) was used as an indicator of recovery in analysis.Three normal phase SPE materials were attempted to separate PAHs in samples,the results indicated that BaP was degraded when passing through florisil.Isotope dilution quantification was recommended to reduce the uncertainty of BaP analysis.Alumina was unsuitable for clean up as for its strong adsorption to PAHs,but silica gel was proved to be the appropriate SPE material among the three candidates.The detection limits for the instrument and the analytical method were in the ranges of 0.26-5.7 pg and 0.067-0.97 ng/g(dry weight),respectively.Recoveries of PAHs in spiked soil ranged from 71% to 122%,with RSDs of 1.6%-8.3%.The method was applied in the analysis of 7 farmland soil samples collected from electronic waste combustion area.The concentrations of PAHs were in the range of 28-283 ng/g(dry weight),the recoveries of BaP-d12 ranged from 90% to 124%,which all fell within the acceptable range set by the QC system. |