烷基酚(alkylphenols)為烷基酚聚乙氧基醇類(alkylphenol polyethoxylates，簡稱APnEOs)非離子型界面活性劑在環境中所降解的產物，已被證實會干擾生物體的內分泌機制，被稱之為環境荷爾蒙(environmental hormones)。此類化學物質近年來引起了大眾的關注，故有必要發展一套既快速又便利的方法檢測環境中的烷基酚類化合物。 在本篇研究中，利用一步完成的微波輔助固相微萃取法(Microwave-Assisted Headspace Solid-Phase Microextraction，簡稱MA-HS-SPME)搭配同位衍生(in situ derivatization)的方式來當作樣品的前處理步驟，再結合氣相層析質譜儀(GC-MS)來偵測水樣中的烷基酚類化合物。取20 mL水樣置於40 mL的棕色瓶中，添加1 g的KHCO3 、300 μL的衍生試劑acetic anhydride及2 g的NaCl，使用65 μm PDMS/DVB的纖維於80 W加熱並萃取5分鐘。偵測極限範圍在2及30 ng/L之間，定量極限範圍在5及50 ng/L之間。 在環境水樣中，4-t-OP與4-NPs以標準添加法定量的結果分別介於142.9至579.8 ng/L和124.8至933.8 ng/L之間，回歸係數高於0.9669。本研究開發的微波輔助頂空固相微萃取法搭配同位衍生，結合氣相層析質譜儀，是具有快速檢測、步驟簡便及穩定性佳的方法，克服傳統萃取法中耗時且需使用大量有機溶劑的缺點，可用來偵測水樣中的烷基酚類化合物。 4-tert-octylphenol (4-t-OP) and 4-nonylphenol isomers (4-NPs) are two persistent degradation products from widely used nonionic surfactants alkylphenol polyethoxylates (APEOs). They have been demonstrated to exhibit the ability to mimic natural hormones. The large-scale usage of surfactants and increasing public concern over environmental issues has stimulated our interest to investigate their occurrence and behavior in the environment. The present study described a rapid and solvent-free procedure for the determination of 4-t-OP and 4-NPs in water samples by one-step in situ acetylated coupled with microwave-assisted headspace solid-phase microextraction (MA-HS-SPME) prior to their determination using gas chromatography-mass spectrometry (GC-MS). The effects of various derivatization and extraction parameters were systematically investigated and optimized. Under optimized conditions, 300 μL of acetic anhydride mixed with 1 g of KHCO3 and 2 g of NaCl in a 20-mL water sample (in a 40-mL sample-bottle) were efficiently extracted by a 65 μm polydimethylsiloxane -divinylbenzene (PDMS-DVB) fiber placed in the headspace when the system was microwave irradiated at 80 W for 5 min. The limits of quantification (LOQs) were 5 and 50 ng/L for 4-t-OP and 4-NPs, respectively. The precision for these analytes, as indicated by relative standard deviations (RSDs), were less than12.9 % for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was between 49.9 – 81.8 % and 27.7 – 63.2 % for 4-t-OP and 4-NPs, respectively. A standard addition method was used to quantitate 4-t-OP and 4-NPs, and the concentrations ranged from 142.9 to 579.8 ng/L and 124.8 to 933.8 ng/L for 4-t-OP and 4-NPs, respectively in various environmental samples. This in situ acetylated MA-HS-SPME appears to be a good alternative extraction method for the determination of 4-t-OP and 4-NPs in environmental samples; it is a simple, effective, low-cost, and eco-friendly analytical method.
