分子拓印暨光子晶體感測器開發與酚甲烷分析之應用

Abstract

酚甲烷(BPA)已被認定為環境荷爾蒙且會存在環境中而影響人體荷爾蒙，本研究針對BPA開發新穎性分子拓印暨光子晶體型元件，並藉由元件與目標化合物結合所引起的折射率與光子能隙變化產生的繞射波長位移量，對標的物進行定量分析。分子拓印利用模板分子-BPA以π-π作用力與官能基單體-苯基三甲氧基矽氧烷(PTMOS)鍵結，並與交連劑-正丙醇鋯(ZPO)聚合形成無機高分子材料。當BPA/PTMOS莫耳比為1時，分子拓印材料對BPA具有良好的吸附能力(4.62 mg/g)以及拓印因子(20.8)。另外，無機分子拓印光子晶體利用模版溶膠凝膠法製備，聚苯乙烯小球(163 nm)先以重力沉降法，於溫度50oC下在玻片上自組裝形成六角最密堆積的蛋白石結構，隨後添加體積為2.5 □L之拓印溶膠溶液充填聚苯乙烯模板間隙，待固化後以溶劑移除模板，便可得到BPA分子拓印暨光子晶體型感測元件，此二氧化鋯反蛋白石結構具有高規則性三維孔洞以及光子能隙4.8 eV(波長 = 257 nm)。當拓印溶膠溶液之ZPO/PTMOS/BPA/乙醇莫耳比為30/1/1/80時，有最佳化微結構，可使分子拓印暨光子晶體元件在偵測50 mg/L BPA過程中於4分鐘內達到吸附平衡，且產生最大波長位移3.2 nm，此元件擁有良好的重複使用性與高線性偵測範圍(1-60 mg/L)，而方法偵測極限為0.41 mg/L。另外，由類似分子酚(phenol)、丁基苯酚(4-tert-butylphenol)以及1-奈酚(1-naphthol)近乎零的波長位移結果可證明感測元件對於目標分子BPA具有高度的選擇性。本研究最後利用寶山水庫原水添加BPA來模擬實際偵測情況，發現感測元件於真實樣品中的線性分析範圍為1至100 mg/L。綜合上述實驗結果，證明本研究製備之分子拓印光子晶體感測器兼具高選擇性及反應快速的特性，為未來極具發展潛力的新型態先進感測器。

Bisphenol A (BPA) is an endocrine disruptor which could cause hormone-related cancers. In this study, a novel imprinted photonic crystal (IPC) was developed for the detection of bisphenol A (BPA). The shifts in the wavelength of the diffraction peaks, resulting from the changed refractive index (n) of the IPC after rebinding of BPA, were adapted for the quantification of the target compound. The molecularly imprinted polymer (MIP) was prepared using a sol-gel method in which zirconium propoxide (ZPO) was used as the cross-linker and phenyltrimethoxysilane (PTMOS) was used as the functional monomer which bound BPA via π-π stacking interaction. The MIP with the PTMOS/BPA molar ratio of 1 had the high adsorption capacity of 4.62 mg/g and imprinted factor of 20.8. Inverse opal photonic crystal was prepared using polystyrene (PS) microspheres (163 nm) as the template. Hexagonal PS colloid crystals was formed through a heat-assisted self-assembly method at 50oC. After infiltration of the colloidal crystals with 2.5 □L imprinted sol solution, the PS microspheres were subsequently removed using solvent extraction. The obtained inverse opal ZrO2 exhibited a photonic bandgap of 4.8 eV (l = 257 nm). The IPC prepared with the ZPO/PTMOS/BPA/EtOH molar ratio of 30/1/1/80 exhibited the optimal microstructures for the largest wavelength shift of 3.2 nm at 50 mg/L BPA. The detection can be completed within 4 min. In addition, a small variation of 4.6% was obtained in 5 detection cycles. The linear detection range in pure water and the raw water from Pao-Shan reservoir was 1-60 and 1-100 mg/L, respectively. The IPC performed insignificant response for BPA analogues including phenol, 1-naphthol and 4-tert-butylphenol (BP), indicating its high selectivity. These results clearly demonstrated that the IPC is an advanced sensing device which can be applied for in-situ and on-site analysis in the future.