Determination of 8 Common Benzene Series in Indoor Air after Home Decoration by Gas Chromatography with Dual Chromatographic Columns and Dual Detectors

In order to solve the problems of false positive results and difficult separation of m-xylene and p-xylene in the determination of benzene series in indoor air after home decoration by gas chromatography with a single chromatographic column and single detector, the title method was proposed. Both ends of the activated carbon adsorption tube were connected to the sampler, and indoor air sample after home decoration was collected for 30 min at flow rate of 1 L·min^-1. After collecting 30 L of gas, the activated carbon adsorption tube was removed and sealed with the polytetrafluoroethylene cap. The activated carbon was taken out from the activated carbon adsorption tube, and 1.00 mL of carbon disulfide was added for desorption at room temperature for 30 min. The resulting gas was introduced into the gas chromatograph at column flow rate of 1.5 mL · min^-1 and split ratio of 1∶5. Eight common benzene series, such as benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene, styrene, and 4-tert-butyl toluene, were passed through a CP-Wax strong polar capillary column (30 m×0.32 mm, 0.25 μm) and a DB-5 weak polar capillary column (30 m×0.25 mm, 0.25 μm) for separation, and detected by dual hydrogen flame ionization detectors. It was shown that the mass concentrations of the 8 benzene series were in a linear relationship with the corresponding peak areas in the range of 0.1-20.0 mg·L^-1, with detection limits (3.143s) in the range of 0.000 3-0.000 5 mg·m^-3. The spiked recovery test was conducted on negative samples at 3 concentration levels, giving recoveries in the range of 96.0%-102%, and RSDs (n=6) of the determined values ranged from 0.30% to 4.9%.