GC-MS Determination of 8 Polycyclic Aromatic Hydrocarbons in Styrene Butadiene Rubber with Separation by Freeze-Grinding and Ultrasonic Extraction

Freeze-grinding and ultrasonic-extraction were applied to separate 8 polycyclic aromatic hydrocarbons (abbrev. as PAHs), including benzo-a-anthracene, chrysene, benzo-b-fluoranthene, benzo-j-fluoranthene, benzo-kfluoranthene, benzo-e-pyrene, benzo-a-pyrene and dibenzo-a,h-anthracene, from samples of styrene butadiene rubber. Five of the rubber samples were selected and cut into small particles sizing 2 mm³. A definite amount of the small sample particles was treated by freeze-grinding in a grinder to give samples in powdered form. 1.00 g of the powdered sample was extracted ultrasonically with 10 mL of a mixture of n-hexane and acetone (1+1), at 40℃ for 35 min. The extract was collected and evaporated to near dryness by N₂-blowing. The residue was taken up with 1 mL of n-hexane, and the solution was filtered through a filtering membrane. The filtrate was used for analysis by GC-MS. GC separation was carried out on the VB-17MS capillary chromatographic column with programed temperature elevation in the interval between 90-300℃. In MS determination, EI ionization source and SIM monitoring mode were adopted. Linearity ranges for the 8 PAHs were found same between 0.05-5.0 mg·L^-1, with detection limits (3S/N) ranged from 0.01 to 0.02 mg·L^-1. Recovery was tested by addition of mixed standard solution of the 8 PAHs to sample solutions as matrixes, giving values of recovery in the range of 84.5% to 106%, and RSDs (n=6) found in the range of 1.6% to 4.9%.