表面塗裝業混存有害物質熱脫附/氣相層析法研究

Method Evaluation for the Measurement of Toxic Organic in Workplace of Surface Coating Industries by Thermodesorption/Gas Chromatography

表面塗裝時所揮發出混存有害物質Toluene, Xylene, Styrene, Butylacetate,等，利用填充固體吸附劑Tenax-TA吸附管採樣再經由熱脫附／氣相層析儀分析的方法已建立。環境中待測物以採樣幫浦抽氣經由Tenax-TA吸附管吸附濃縮後，再放入200°C的熱脫附儀中熱脫附6分鐘，熱脫附時先經由自製分流裝置分流後再進入冷凝濃縮微管，並以-60°C的溫度將之冷凝濃縮於微管中，再以1200°C/min的快速升溫注入氣相層析儀中分析，使用DB-WAX管柱（30m x 0.53 nun;膜厚1μm）可將上述的待測物完全分離。在溫度30±3°C與相對濕度80±5％及待測物在二倍容許濃度實驗條件下，以n-butylacetate的破出體積最小，約為1公升左右。所有待測化合物在15天的測試中，不論在常溫或冷凍貯存均很安定。熱脫附回收率在94.8％～101.2％之間，所建立的分析方法與傳統活性碳－溶劑脫附法做現場比對，結果並沒明顯差異。此法用於三種噴漆室（開放、半開放與密閉）做實際樣品採樣分析，所得結果顯示總污染量在容許濃度值範圍內。

A method for the measurement of toluene, xylene, styrene and butylacetate in workplace of surface coating industries was developed. The target compounds were adsorbed on Tenax-TA (60~80 mesh) tube by sampling pump, then thermodesorbed into a thermodesorption/gas chromatograph equipped with flame ionization detector for the analysis. All the compounds can be separated completely by a DB-WAX capillary column (30m x 0.53mm ; Film thickness 1μm). Breakthrough volume was determined by photoionization analyser under the condition of 30±3°C and 80 ± 5 (% relative humidity) with the concentration level of twice the permissible exposure limit (PEL). Results showed the smallest breakthrough volume was one liter for butylacetate. The recovery yield of this method was in the range of 94.8 %~101.2 %. All the compounds can be stored safely within 15 days in both room and freezing temperature. Further, results from the established method and from the method of charcoal sampling with solvent extraction for the field measurement showed that there was no significant difference between these two methods. Finally, the methodology had been tested in three different types of surface coating workplace (i.e. open, semi-open, closed system). All concentration of the target compounds were below the permissible exposure limit level.