Abstract: A new solid phase microextraction (SPME) fiber coated with activated charcoal was estimated by determination of benzene, toluene and xylene（BTX）in indoor air. There is linear relationship between the amount of BTX extracted by the SPME and gas volume at ≤100mL of gas volume. The correlation coefficient (R2) of these linear equations is better than 0.99.The linear equations between amounts of BTX extracted and concentration of BTX in gas are Y=115.89x＋1.919 with correlation coefficient(R2) of 0.999 for benzene，Y=112.29x－7.176 with 0.999 of R2 for toluene，Y=112.29x－7.176 with 0.999 of R2 for p-xylene，ranging concentration from 0.088 to 8.8ng/mL. There are the linear relationship equations with better R2 of 0.997 between the reciprocal of amounts of BTX extracted and the reciprocal of gas volume. The sorption coefficients（K）are 3.9×106, 2.6×107 and 3.2×107 for benzene，toluene and p-xylene，respectively. The extraction recovery are 97.2%，98.9% and 96.4% for benzene，toluene and p-xylene，respectively.The mean relative standard deviation (RSD) and relative error (RE) are 7.47% and 3.38% for BTX, respectively. Detection limits are 1.7×10－3，2.3×10－3　and 2.3×10－3ng/mL for benzene，toluene and p-xylene，respectively. Linear ranges of 104 are achieved for BTX. The maximum amount of the adsorbed for BTX is 3μg.

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

摘要： 对研制的活性炭涂层固相微萃取进样器进行了评价。建立了活性炭涂层固相微萃取/热脱附法测定气体中苯、甲苯和对-二甲苯的方法。测定了萃取量与样品体积和组分浓度间的关系。当样品浓度≤10ng/mL时，萃取量与浓度存在线性关系,相关系数≥0.998。当采样体积≤100mL时，萃取量与样品体积存在线性关系。利用改变样品体积方法测定了组分的吸附常数，实验测定萃取量倒数与样品体积倒数之间的线性方程的相关系数≥0.997， 活性炭涂层对苯、甲苯和对-二甲苯的吸附常数分别为3.9×106，2.6×107和3.2×106。实测BTX的相对标准偏差 （RSD）≤9%,回收率≥97%， 检出限达到pg/mL数量级，对BTX的最大吸附量3μg。

关键词: 活性炭涂层固相微萃取, 热脱附, 苯, 甲苯, 对-二甲苯, 室内空气