双色谱柱双检测器气相色谱法测定家装室内空气中8种常见苯系物的含量

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

为解决以单色谱柱单检测器气相色谱法测定家装室内空气中苯系物含量时易出现假阳性结果以及间二甲苯和对二甲苯难分离等问题,提出了题示方法。将活性炭吸附管两端与采样器相连,以1 L·min^(-1)流量采集家装室内空气样品30 min,采集30 L气体后取下活性炭吸附管,用聚四氟乙烯帽密封。取出活性炭吸附管中的活性炭,加入1.00 mL二硫化碳,于室温解吸30 min,所得溶液在柱流量1.5 mL·min^(-1)、分流比1∶5条件下进入气相色谱仪,苯、甲苯、乙苯、邻二甲苯、间二甲苯、对二甲苯、苯乙烯和4-叔丁基甲苯等8种常见苯系物分别经过CP-Wax强极性毛细管色谱柱(30 m×0.32 mm, 0.25μm)和DB-5弱极性毛细管色谱柱(30 m×0.25 mm, 0.25μm)分离后,用双氢火焰离子化检测器分别测定。结果显示:8种苯系物的质量浓度均在0.1~20.0 mg·L^(-1)内与对应的峰面积呈线性关系,检出限(3.143s)为0.000 3~0.000 5 mg·m^(-3)。对阴性样品进行3个浓度水平的加标回收试验,回收率为96.0%~102%,测定值的相对标准偏差(n=6)为0.30%~4.9%。

In order to solve the problems of false positive results and difficult separation of m-xylene and pxylene 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 30min at flow rate of 1L·min^(-1).After collecting 30Lof 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 1.00mL of carbon disulfide was added for desorption at room temperature for 30min.The resulting gas was introduced into the gas chromatograph at column flow rate of 1.5mL·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(30m×0.32mm,0.25μm)and a DB-5weak polar capillary column(30m×0.25mm,0.25μm)for separation,and detected by dual hydrogen flame ionization detectors.It was shown that the mass concentrations of the 8benzene series were in a linear relationship with the corresponding peak areas in the range of 0.1-20.0mg·L^(-1),with detection limits(3.143s)in the range of 0.0003-0.0005mg·m^(-3).The spiked recovery test was conducted on negative samples at 3concentration 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%.