| 摘要: | 對-羥基苯甲酸酯 (Alkyl p-hydroxybenzoate, 又稱parabens) 因其價格低廉、無味，不易硬化，常用作個人護理產品的防腐劑，例如：沐浴乳和化妝品中，也添加於藥品以及食物中。但研究發現parabens可能有雌激素活性、致癌性，是潛在的內分泌干擾物質，又因環境基質複雜，濃度相對低了許多，因此，開發一套具有高選擇性的方法用以檢測環境中對-羥基苯甲酸酯的含量是不可或缺的趨勢。
分子拓印 (Molecularly imprinting) 是一種新興的技術可用於製備對特定化學分子具高專一性鍵結位置之材料。本實驗使用自組裝法，以氫鍵的方式將拓印的模板分子和官能基單體進行結合。以對-羥基苯甲酸乙酯 (EtP) 作為模板分子、甲基丙烯酸 (MAA) 為官能基單體、乙二醇二甲基丙烯酸酯 (EGDMA) 作為交聯劑、偶氮二異丁腈 (AIBN) 為起始劑，將其配製於溶劑中，之後與PVA水溶液混合，利用懸浮聚合法進行聚合反應，並以索氏萃取將模板分子洗出，完成分子拓印聚合物 (Molecularly imprinted polymer, MIP) 製備。透過SEM觀察，其確實具有微球的型態。
本研究利用製備出來的MIP作為固相萃取 (Solid-phase extraction, SPE) 具選擇性的吸附劑，藉由分子拓印聚合物的高選擇性，將四種常見的parabens從環境水樣中萃取出來，並用超高效液相層析串聯質譜儀檢測水樣中parabens的含量。
分子拓印固相萃取最佳化條件為：50 mg的吸附劑填充到固相萃取管匣中，以2 mL甲醇作為沖提溶劑做萃取，經過吹氮，以100 μL的甲醇回溶，進到UHPLC-QTOF-MS進行檢測。在0.15-2 μg/L的濃度範圍內，檢量線回歸係數R2皆在0.994以上；偵測極限 (LOD) 為0.040-0.045 μg/L。在精密度與準確度的測試，其相對標準偏差 (RSDs) 皆小於9 %，顯示此方法具有良好的穩定性及再現性。在台灣不同的水樣中測得的parabens濃度介於0.17-5.33 μg/L之間。
;Alkyl p-hydroxybenzoate, also known as parabens, have been added in personal care products as preservatives for many years. Because of its low prices, odorless and difficult hardening, they are used widely. However, the studies show that parabens may contain estrogen activity and carcinogen activity, and they are potential endocrine disruptors. Moreover, complicated environmental matrix leads to lower concentration of parabens. Therefore, developing a highly selective method to extract parabens from environmental water samples is very important.
Molecularly imprinting technology has been used for preparation of polymers and it can be a high selectivity method for the target molecules analysis. According to the interaction between template molecule and functional monomer, it can be divided into pre-organized approach and self-assembly approach. In this study, using self-assembly approach to prepare molecularly imprinted polymer (MIP). Ethyl paraben (EtP) was used as template molecule, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker and 2,2’-azobis-isobutyronitrile (AIBN) as the initiator. The molecularly imprinted polymer has been synthesized using suspension polymerization. After polymerization, the polymer was washed by Soxhlet apparatus until no template could be detect. The molecularly imprinted polymer was proved to have a homogeneous spherical structure by SEM.
A solid-phase extraction based on MIP procedure was used to extract four parabens from water samples. The optimal extraction conditions were packing 50 mg MIP and elution with 2 mL methanol, the eluent was dried under nitrogen and reconstituted with 100 μL methanol. The sample was analyzed by UHPLC-QTOF-MS.
The method showed a good linearity in range of 0.15-2 μg/L. The regression coefficients (R2) exceeded 0.994, and the limit of detection (LOD) were a range from 0.040-0.045 μg/L. The method also had good accuracy (recovery 93-105%) and precision (RSD < 9%). In real samples, parabens were detected between 0.17-5.33 μg/L in Taiwan. |
