奈米氧化鐵薄膜應用於電抗式微小化氣相層析偵測器之研製

Abstract

本研究基於奈米氧化鐵特有的磁性性質，將其作為自製偵測器之材料，並分析其電氣參數，研究其在高頻時量測不同種類的揮發性有機氣體VOCs之電抗變化現象。在奈米氧化鐵粒子表面修飾油酸分子，使其能以穩定的膠體溶液形式存在，塗覆在微製程加工之叉指電極上，後經加工組合成氣相層析偵測器，並串接於桌上型氣相層析儀之後，對11種有機氣體進行量測，結果均顯示良好的線性關係(R2>0.99)、靈敏度與再現性。根據實驗結果，本研究之奈米氧化鐵薄膜偵測器對高沸點、高極性的化合物有較佳的感測靈敏度，以anisole為例，其偵測下限甚至能達20 ng之下，並也從研究中發現自製偵測器有利於偵測鹵烷類化合物。 此外，將奈米氧化鐵替換成以十六烷硫醇修飾之奈米銀，以相同的製作手法製作偵測器，並與之相互比較，結果顯示奈米氧化鐵的訊號強度相較於奈米銀大上數倍，顯現出奈米氧化鐵之獨特性。

Based on the magnetic properties of nano-iron oxide, this study uses it as a material for home-made detectors, and its electrical parameters are analyzed, and its reactance to different kinds of volatile organic gas (VOCs) is measured at high frequencies. The surface of iron oxide nanoparticle is modified with oleic acid so that they can exist in the form of stable colloidal solution, and then coated on the interdigital electrode(IDE) processed by micro-process, combined into a gas chromatography detector, which is connected in series with the desktop gas chromatograph(GC) to detect eleven organic gases, and the results all showed a good linear relationship (R2>0.99), sensitivity and reproducibility. According to the experimental results, the iron oxide nanofilm detector in this study has better sensing sensitivity for compounds with high boiling point and high polarity. Taking anisole as an example, its detection limit can even below 20 ng, and it is also found from the study that the home-made detector is beneficial to detect halogenated compounds. In addition, the iron oxide nanoparticle was replaced with silver nanoparticle modified with hexadecyl mercaptan and compared with each other by the same experiment method. The results showed that the signal intensity of the iron oxide nanoparticles was higher is several times larger than that of silver nanoparticle, showing the uniqueness of iron oxide nanoparticles.