热解吸／化学发光联用技术检测空气中痕量苯

Detection of Trace Benzene in Air Using Thermal Desorption/Chemiluminescence

自组装一种新型的热解吸/化学发光的仪器系统,据此建立了一种测定空气中痕量苯的新方法,并对比研究了不同吸附剂对苯的吸附性能。实验表明,Tenax-TA(2,6-二苯基对苯醚的多孔聚合物)对空气中低浓度的苯具有较好吸附效果。当从吸附剂解吸的苯蒸汽通过氧化钇(Y2O3)粉体表面时,其催化发光强度与苯浓度在相当宽的范围内呈良好的线性关系,其线性范围为0.44～44mg/m3(r=0.9991,n=9),检出限为0.1mg/m3(S/N=3);对浓度为0.44mg/m3的苯气体平行测定了9次,其相对标准偏差为4.45%;Tenax-GR(2,6-二苯并呋喃聚合物树脂加上30%石墨碳)对低浓度苯的吸附效果更好,其线性范围为0.22～22mg/m3(r=0.9922,n=9);检出限为0.07mg/m3(S/N=3)。本方法耗时短、简便快速,成功实现了对苯的实时在线检测。

A method based on the thermal desorption/catalytic chemiluminescence was applied to determine the concentration of trace benzene in air. The effects of absorption properties of different kinds of adsorbents on benzene was studied. Experimental result indicated that the adsorption of benzene on Tenax-TA（2,6-diphenylp-phenylene oxide） had high stability. Catalytic luminescence intensity was linear to the concentration of benzene in a wide range. The linear range was 0.44 -44 mg/m^3 （r =0. 9991, n =9）, the detection limit was 0.1 mg/m^3 （ the signal-to-noise ratio was 3 ）. To 0.44 mg/m^3 benzene gas, the luminuecence intensity was detemined for 9 times, and RSD was 4.5%. The adsorbent, Tenax-GR（2,6-diphenylene-oxide polymer resin plus 30% graphite）, was suitable for the determination of concentration of benzene, the linear range was 0.22 - 22 mg/m^3 （ r = O. 9922, n = 9）, the determination limit was 0. 07 mg/m^3 （ the signal-to-noise ratio was 3 ）. This method has the advantages of short time-consuming and performance stability. It has been successfully applied to the online determination of benzene.