作業環境空氣中酚之熱脫附氣相層析分析方法

Analysis of Phenol in Workplace Air Using Thermal Desorption Gas Chromatographic Technique

作業環境空氣中酚的定量方法，先前是以盛裝NaOH的衝擊瓶採樣後，用高效能液相層析儀（HPLC）分析，這種方法必須攜帶試劑溶液及玻璃器皿至採樣現場，造成採樣工作的不方便，且不易自動化，HPLC的解析度也不足以分離各種酚類化合物。本研究用填充Tenax-TA吸附劑的採樣管採集空氣中的酚後，利用熱脫附裝置將樣品脫附後直接送入氣相層析儀分析，根據美國EPA的35°C破出體積計算，本研究所用吸附劑之最大採樣體積為2.75L，不論室溫遮光保存或冷藏保存時，樣品的儲存穩定度都大於15天，在0.5、1和2倍PEL濃度下的回收率分別為97.3％、98.5％及101.8％，回收率的總變異係數為4.06％，六次重複分析之精密度相對標準偏差< 6％，方法偵測極限為1.14μg。

NIOSH and IOSH have been using the impinger technique for sampling and analysis of phenol with HPLC. This sampling technique is quite troublesome because it needs to handle chemical solutions and glasswares in fields. Besides, HPLC does not offer sufficient resolution for phenol. Thus, the employment of GC for analysis was tried in this study. Tenax TA is chosen as the adsorbent for phenol because of its high breakthrough volume, capable of taking reasonably high temperature and very low retention of water. After thermal desorption, the sample was directly sent to GC for analysis. The largest sampling volume of the sorbent, 2.75L, was calculated according to the breakthrough volume at 35°C of US EPA TO-1 method. Sample stability was found to be longer than 15 days both at room temperature and -30°C. The recoveries at 0.5, 1.0 and 2.0 PEL were 97.3%, 98.5% and 101.8%, respectively. The analysis coefficient of variation (CVa%) was 4.06%. Relative standard deviation of six repeated analyses of three different concentrations were all < 6%. Method detection limit was 1.14μg.