Fabrication of stable copper nanoparticles embedded in nanocellulose film as a bionanocomposite plasmonic sensor and thereof for optical sensing of cyanide ion in water samples

Herein, an optical plasmonic chemosensor was fabricated via in situ embedding of stable copper nanoparticles (Cu NPs) within flexible nanocellulose film (ECNPs-NC film) utilized for optical sensing of cyanide (CN⁻). Glycerol, as a plasticizer, was added to the nanocellulose suspension to improve ductility of nanocellulose-based film. In addition, to enhance the stability of Cu NPs against oxidizing and corrosion, the fabricated ECNPs-NC film was immersed and coated by benzotriazole solution. The Cu NPs were stable for 4 months. The fabricated ECNPs-NC film was characterized by various methods such as field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopic, dynamic light scattering, thermo-gravimetric analysis, and energy-dispersive X-ray spectroscopy. Analytical parameters influencing the efficiency of ECNPs-NC film fabrication were investigated and optimum conditions were stablished. The fabricated ECNPs-NC film was applied as a novel optical sensor for CN⁻ detection in water samples. By changing in CN⁻ concentration, surface plasmon resonance absorption intensity was changed and it was linear in the range of 0.25–0.40 µg mL⁻¹ with a detection limit of 0.015 µg mL⁻¹.