短鏈氯化石蠟(short chain chlorinated paraffins, SCCPs) 是指碳鏈長度為10 至13 且氯含量介於30%至72%之間的直鏈氯化烷烴。 短鏈氯化石蠟具有持久性、生物累積性以及經由大氣進行遠距離遷移 的能力，斯德哥爾摩公約(Stockholm Convention) 目前也擬將短鏈氯 化石蠟增列為優先控制之持久性有機物染物(persistent organic pollutants, POPs)。因此開發一套簡單、有效率且穩固的方法來檢測環 境中的短鏈氯化石蠟是勢在必行的。 本研究以震盪輔助式液液微萃取法(vortex-assisted liquid-liquid microextraction, VALLME) 為前處理方法，並搭配氣相層析電子捕捉 負離子質譜儀(GC/ECNI-MS) 對水樣中的短鏈氯化石蠟進行檢測。 震盪輔助式液液微萃取法的最佳化條件為：取400 μL 的二氯甲烷 快速注入20 mL 的水樣中，接著使用多功能震盪機以2500 rpm 高速 震盪1 分鐘，再以4500 rpm 的轉速離心3 分鐘，使有機層與水層分 離，隨後取出有機沉澱相並以吹氮回溶至10 μL，最終取1 μL 進樣於 GC/ECNI-MS 進行分析。偵測極限(limit of detection, LOD) 為0.02 μg/L。在inter-days 及intra-day 的測試中，其所得相對標準偏差(RSDs) 皆小於9%，顯示本方法具有良好的再現性與穩定性。在國內不同水 樣中所測得的短鏈氯化石蠟濃度為0.08 至0.16 μg/L。 ;Short chain chlorinated paraffins (SCCPs) are polychlorinated n-alkanes with carbon chain lengths from 10 to 13 and a chlorination degree between 30 and 72% by mass. SCCPs are resistant to environmental degradation and also have characteristics such as bioaccumulation and long-range transport. A global ban on SCCPs is being considered under the Stockholm Convention on Persistent Organic Pollutants, so it is necessary to develop a simple, efficient and robust method to monitor SCCPs in the environment. In this study, vortex-assisted liquid-liquid microextraction (VALLME) coupled with GC/ECNI-MS was developed and used to determine SCCPs in water samples. The optimized procedure of VALLME were as follows: 400 μL of dichloromethane was rapidly injected into a 20 mL water sample. After vortex for 1 min at 2500 rpm and centrifugation for 3 min at 4500 rpm, the mixture became a two-phase solution. Then the sedimented phase was transferred to the vial and evaporated to dryness by a gentle stream of nitrogen. Prior to analysis, 10 μL of acetone containing internal standard was added in the vial and 1μL was injected into GC/ECNI-MS for analysis.We also used a method termed vortex-assisted enrichment-enhanced liquid-liquid microextraction (VAEELLME) in the analysis of real water samples.With this method, we can obtain higher enrichment and lower detection limit. The limit of detection (LOD) for SCCPs in water samples was determined to be 0.02 μg/L. The relative standard deviations (RSDs) of inter-days and intraday tests were lower than 9% and the SCCPs levels in water samples ranged from 0.08 to 0.16 μg/L.
