Abstract: A new solid phase microextraction (SPME) fiber coated with porous layer activated charcoal has been developed for the quantification of benzene in gas. There is a linear relationship between the amount of benzene extracted by the SPME coated with porous layer activated charcoal and gas volume (V_g) at ≤100mL of gas phase volume. The linear equation is A=25.815V_g+36.462 with correlation coefficient (R²) of 0.999. The linear equation between amounts of benzene extracted by the SPME coated with porous layer activated charcoal and concentration of benzene (C) in gas phase is A=140.09C+16.24 with correlation coefficient (R²) of 0.996, ranging of concentration from 0.0879 to 52ng·mL^-1. The linear equation between the reciprocal of amounts of benzene extracted (1/A) and the reciprocal of gas volume (1/V_g) is 1/A=0.11805/V_g+0.00011, with correlation coefficient (R²) of 0.9999. The extraction recovery and sorption coefficient (K)for benzene are 92.47% and 2.15×10⁶, respectively. The relative standard deviation (RSD) and relative error (RE) are 6.98% and 7.50% for benzene, respectively. Detection limit of 5.86×10^-3ng·mL^-1 and linear range of 10.4 are measured. The maximum amount of the adsorbed benzene is 2636ng. The results obtained by use of this porous layer activated charcoal fiber are also compared with results obtained by use of a polydimethylsiloxane(PDMS) coated fiber(SUPELCO, USA).

Key words: solid phase microextraction, thermal desorption, benzene, indoor air

摘要： 研制了活性炭涂层固相微萃取进样器。推导了萃取量与样品体积和组分浓度间的数学关系式。建立了活性炭涂层固相微萃取/热脱附法测定气体中苯的方法。提出了改变样品体积测定组分浓度和吸附常数的方法。当采样体积≤100mL时，萃取量与样品体积存在线性关系。样品浓度≤52ng·mL^-1 时，萃取量与浓度的线性关系为 A=140.09C+16.24，相关系数0.996。实验测定萃取量倒数与样品体积倒数的线性方程为：1/A=0.11805/V_g+0.00011，相关系数R²=0.999，活性炭涂层对苯的吸附常数为2.15×10⁶。实测苯的相对标准偏差（RSD）<6.98% (n=6)，相对误差7.50%，检出限是5.86×10^-6ng·mL^-1，线性范围10⁴，对苯的最大吸附量2636ng，灵敏度比商品固相微萃取（PDMS）高近50倍。

关键词: 活性炭涂层固相微萃取, 热脱附, 苯, 室内空气