Nanostructured Chitosan/Maghemite Composites Thin Film for Potential Optical Detection of Mercury Ion by Surface Plasmon Resonance Investigation

• Main Authors: Nurul Illya Muhamad Fauzi, Yap Wing Fen, Nur Alia Sheh Omar, Silvan Saleviter, Wan Mohd Ebtisyam Mustaqim Mohd Daniyal, Hazwani Suhaila Hashim, Mohd Nasrullah
• Format: Article
• Language: English
• Published: MDPI AG 2020-07-01
• Series: Polymers
• Subjects: chitosan; maghemite; optical; mercury ion; surface plasmon resonance
• Online Access: https://www.mdpi.com/2073-4360/12/7/1497

In this study, synthesis and characterization of chitosan/maghemite (Cs/Fe₂O₃) composites thin film has been described. Its properties were characterized using Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and ultraviolet-visible spectroscopy (UV-Vis). FTIR confirmed the existence of Fe–O bond, C–N bond, C–C bond, C–O bond, O=C=O bond and O–H bond in Cs/Fe₂O₃ thin film. The surface morphology of the thin film indicated the relatively smooth and homogenous thin film, and also confirmed the interaction of Fe₂O₃ with the chitosan. Next, the UV-Vis result showed high absorbance value with an optical band gap of 4.013 eV. The incorporation of this Cs/Fe₂O₃ thin film with an optical-based method, i.e., surface plasmon resonance spectroscopy showed positive response where mercury ion (Hg²⁺) can be detected down to 0.01 ppm (49.9 nM). These results validate the potential of Cs/Fe₂O₃ thin film for optical sensing applications in Hg²⁺ detection.