| Summary: | 碩士 === 國立臺灣大學 === 環境衛生研究所 === 91 === Trimethylbenzene (TMB) is a prevalent component of commercially available solvent mixtures and gasoline. Exposure to TMB causes adverse effects on respiratory system and nervous system. To develop a proper way for sampling and analysis, solid phase microextraction (SPME) was explored to become a passive sampler for TMB. The 26 ppm and 53 ppm TMB were generated by dynamically injecting the mixture of 1,3,5-TMB, 1,2,4-TMB and 1,2,3-TMB into the atmosphere at temperature of 25.1 ± 0.6 ℃, relative humidity of 66 ± 5 % and flow rate of 1360 ± 38 ml/min. The reference TMB was collected by the SPME fiber of 30μm polydimethylsiloxane as a passive sampler and thermally desorbed into GC/MS for quantification, in order to determine the optimized condition for thermal desorption, the sampling rates and the storage stability. As samples were desorbed at 250℃ for 1 min, the sampling rates in average with coefficient of variance within 10% were 5.88×10-5 cm3/sec for 1,3,5-TMB, 6.24×10-5 cm3/sec for 1,2,4-TMB and 6.14×10-5 cm3/sec for 1,2,3-TMB. The instrument detection limits were 0.128 ng, 0.133ng and 0.128 ng in order of 1,3,5-TMB, 1,2,4-TMB and 1,2,3-TMB. The recovery rates for samples stored at －70℃ for an hour were close to 80%. In conclusion, sampling rates remain consistent in sampling 1 PEL(25ppm) or 2 PEL TMB for 5 minutes to 25 minutes with the 30μm polydimethylsiloxane SPME and to sample TMB at 1 PEL, the SPME fiber can collect enough amount of TMB for GC/MS analysis even the sampling time is as short as 5 minutes.
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